diff --git a/src/allmydata/client.py b/src/allmydata/client.py
index fa515d4..46b02bc 100644
--- a/src/allmydata/client.py
+++ b/src/allmydata/client.py
@@ -6,7 +6,6 @@ from zope.interface import implements
 from twisted.internet import reactor, defer
 from twisted.application import service
 from twisted.application.internet import TimerService
-from foolscap.api import Referenceable
 from pycryptopp.publickey import rsa
 
 import allmydata
@@ -22,7 +21,7 @@ from allmydata.util.abbreviate import parse_abbreviated_size
 from allmydata.util.time_format import parse_duration, parse_date
 from allmydata.stats import StatsProvider
 from allmydata.history import History
-from allmydata.interfaces import IStatsProducer, RIStubClient
+from allmydata.interfaces import IStatsProducer
 from allmydata.nodemaker import NodeMaker
 
 
@@ -32,9 +31,6 @@ GiB=1024*MiB
 TiB=1024*GiB
 PiB=1024*TiB
 
-class StubClient(Referenceable):
-    implements(RIStubClient)
-
 def _make_secret():
     return base32.b2a(os.urandom(hashutil.CRYPTO_VAL_SIZE)) + "\n"
 
@@ -186,7 +182,8 @@ class Client(node.Node, pollmixin.PollMixin):
         ic = IntroducerClient(self.tub, self.introducer_furl,
                               self.nickname,
                               str(allmydata.__full_version__),
-                              str(self.OLDEST_SUPPORTED_VERSION))
+                              str(self.OLDEST_SUPPORTED_VERSION),
+                              self.get_app_versions())
         self.introducer_client = ic
         # hold off on starting the IntroducerClient until our tub has been
         # started, so we'll have a useful address on our RemoteReference, so
@@ -292,7 +289,6 @@ class Client(node.Node, pollmixin.PollMixin):
         self.terminator = Terminator()
         self.terminator.setServiceParent(self)
         self.add_service(Uploader(helper_furl, self.stats_provider))
-        self.init_stub_client()
         self.init_nodemaker()
 
     def init_client_storage_broker(self):
@@ -331,20 +327,6 @@ class Client(node.Node, pollmixin.PollMixin):
     def get_storage_broker(self):
         return self.storage_broker
 
-    def init_stub_client(self):
-        def _publish(res):
-            # we publish an empty object so that the introducer can count how
-            # many clients are connected and see what versions they're
-            # running.
-            sc = StubClient()
-            furl = self.tub.registerReference(sc)
-            ri_name = RIStubClient.__remote_name__
-            self.introducer_client.publish(furl, "stub_client", ri_name)
-        d = self.when_tub_ready()
-        d.addCallback(_publish)
-        d.addErrback(log.err, facility="tahoe.init",
-                     level=log.BAD, umid="OEHq3g")
-
     def init_nodemaker(self):
         self.nodemaker = NodeMaker(self.storage_broker,
                                    self._secret_holder,
diff --git a/src/allmydata/interfaces.py b/src/allmydata/interfaces.py
index 48094a9..9c2f1c8 100644
--- a/src/allmydata/interfaces.py
+++ b/src/allmydata/interfaces.py
@@ -26,14 +26,6 @@ WriteEnablerSecret = Hash # used to protect mutable bucket modifications
 LeaseRenewSecret = Hash # used to protect bucket lease renewal requests
 LeaseCancelSecret = Hash # used to protect bucket lease cancellation requests
 
-class RIStubClient(RemoteInterface):
-    """Each client publishes a service announcement for a dummy object called
-    the StubClient. This object doesn't actually offer any services, but the
-    announcement helps the Introducer keep track of which clients are
-    subscribed (so the grid admin can keep track of things like the size of
-    the grid and the client versions in use. This is the (empty)
-    RemoteInterface for the StubClient."""
-
 class RIBucketWriter(RemoteInterface):
     """ Objects of this kind live on the server side. """
     def write(offset=Offset, data=ShareData):
diff --git a/src/allmydata/introducer/client.py b/src/allmydata/introducer/client.py
index 31fbb5c..1e48fd8 100644
--- a/src/allmydata/introducer/client.py
+++ b/src/allmydata/introducer/client.py
@@ -1,29 +1,73 @@
 
-from base64 import b32decode
+import time, simplejson
 from zope.interface import implements
 from twisted.application import service
-from foolscap.api import Referenceable, SturdyRef, eventually
+from foolscap.api import Referenceable, eventually, RemoteInterface, Violation
 from allmydata.interfaces import InsufficientVersionError
-from allmydata.introducer.interfaces import RIIntroducerSubscriberClient, \
-     IIntroducerClient
+from allmydata.introducer.interfaces import IIntroducerClient, \
+     RIIntroducerSubscriberClient_v1, RIIntroducerSubscriberClient_v2
+from allmydata.introducer.common import sign, unsign, make_index, \
+     convert_announcement_v1_to_v2, convert_announcement_v2_to_v1
 from allmydata.util import log, idlib
-from allmydata.util.rrefutil import add_version_to_remote_reference, trap_deadref
+from allmydata.util.rrefutil import add_version_to_remote_reference
+from allmydata.util.ecdsa import BadSignatureError
+
+class ClientAdapter_v1(Referenceable): # for_v1
+    """I wrap a v2 IntroducerClient to make it look like a v1 client, so it
+    can be attached to an old server."""
+    implements(RIIntroducerSubscriberClient_v1)
+
+    def __init__(self, original):
+        self.original = original
+
+    def remote_announce(self, announcements):
+        lp = self.original.log("received %d announcements (v1)" %
+                               len(announcements))
+        anns_v1 = set([convert_announcement_v1_to_v2(ann_v1)
+                       for ann_v1 in announcements])
+        return self.original.got_announcements(anns_v1, lp)
+
+    def remote_set_encoding_parameters(self, parameters):
+        self.original.remote_set_encoding_parameters(parameters)
+
+class RIStubClient(RemoteInterface): # for_v1
+    """Each client publishes a service announcement for a dummy object called
+    the StubClient. This object doesn't actually offer any services, but the
+    announcement helps the Introducer keep track of which clients are
+    subscribed (so the grid admin can keep track of things like the size of
+    the grid and the client versions in use. This is the (empty)
+    RemoteInterface for the StubClient."""
+
+class StubClient(Referenceable): # for_v1
+    implements(RIStubClient)
 
 
 class IntroducerClient(service.Service, Referenceable):
-    implements(RIIntroducerSubscriberClient, IIntroducerClient)
+    implements(RIIntroducerSubscriberClient_v2, IIntroducerClient)
 
     def __init__(self, tub, introducer_furl,
-                 nickname, my_version, oldest_supported):
+                 nickname, my_version, oldest_supported,
+                 app_versions):
         self._tub = tub
         self.introducer_furl = introducer_furl
 
         assert type(nickname) is unicode
-        self._nickname_utf8 = nickname.encode("utf-8") # we always send UTF-8
+        self._nickname = nickname
         self._my_version = my_version
         self._oldest_supported = oldest_supported
+        self._app_versions = app_versions
+
+        self._my_subscriber_info = { "version": 0,
+                                     "nickname": self._nickname,
+                                     "app-versions": self._app_versions,
+                                     "my-version": self._my_version,
+                                     "oldest-supported": self._oldest_supported,
+                                     }
+        self._stub_client = None # for_v1
+        self._stub_client_furl = None
 
-        self._published_announcements = set()
+        self._published_announcements = {}
+        self._canary = Referenceable()
 
         self._publisher = None
 
@@ -33,10 +77,11 @@ class IntroducerClient(service.Service, Referenceable):
 
         # _current_announcements remembers one announcement per
         # (servicename,serverid) pair. Anything that arrives with the same
-        # pair will displace the previous one. This stores unpacked
-        # announcement dictionaries, which can be compared for equality to
-        # distinguish re-announcement from updates. It also provides memory
-        # for clients who subscribe after startup.
+        # pair will displace the previous one. This stores tuples of
+        # (unpacked announcement dictionary, verifyingkey, rxtime). The ann_d
+        # dicts can be compared for equality to distinguish re-announcement
+        # from updates. It also provides memory for clients who subscribe
+        # after startup.
         self._current_announcements = {}
 
         self.encoding_parameters = None
@@ -51,6 +96,11 @@ class IntroducerClient(service.Service, Referenceable):
             "new_announcement": 0,
             "outbound_message": 0,
             }
+        self._debug_outstanding = 0
+
+    def _debug_retired(self, res):
+        self._debug_outstanding -= 1
+        return res
 
     def startService(self):
         service.Service.startService(self)
@@ -95,22 +145,14 @@ class IntroducerClient(service.Service, Referenceable):
 
     def log(self, *args, **kwargs):
         if "facility" not in kwargs:
-            kwargs["facility"] = "tahoe.introducer"
+            kwargs["facility"] = "tahoe.introducer.client"
         return log.msg(*args, **kwargs)
 
-
-    def publish(self, furl, service_name, remoteinterface_name):
-        assert type(self._nickname_utf8) is str # we always send UTF-8
-        ann = (furl, service_name, remoteinterface_name,
-               self._nickname_utf8, self._my_version, self._oldest_supported)
-        self._published_announcements.add(ann)
-        self._maybe_publish()
-
     def subscribe_to(self, service_name, cb, *args, **kwargs):
         self._local_subscribers.append( (service_name,cb,args,kwargs) )
         self._subscribed_service_names.add(service_name)
         self._maybe_subscribe()
-        for (servicename,nodeid),ann_d in self._current_announcements.items():
+        for (servicename,nodeid),(ann_d,key,when) in self._current_announcements.items():
             if servicename == service_name:
                 eventually(cb, nodeid, ann_d)
 
@@ -124,87 +166,139 @@ class IntroducerClient(service.Service, Referenceable):
                 # there is a race here, but the subscription desk ignores
                 # duplicate requests.
                 self._subscriptions.add(service_name)
-                d = self._publisher.callRemote("subscribe", self, service_name)
-                d.addErrback(trap_deadref)
-                d.addErrback(log.err, format="server errored during subscribe",
-                             facility="tahoe.introducer",
+                self._debug_outstanding += 1
+                d = self._publisher.callRemote("subscribe_v2",
+                                               self, service_name,
+                                               self._my_subscriber_info)
+                d.addBoth(self._debug_retired)
+                d.addErrback(self._subscribe_handle_v1, service_name) # for_v1
+                d.addErrback(log.err, facility="tahoe.introducer.client",
                              level=log.WEIRD, umid="2uMScQ")
 
+    def _subscribe_handle_v1(self, f, service_name): # for_v1
+        f.trap(Violation, NameError)
+        # they don't have a 'subscribe_v2' method: must be a v1 introducer.
+        # Fall back to the v1 'subscribe' method, using a client adapter.
+        ca = ClientAdapter_v1(self)
+        self._debug_outstanding += 1
+        d = self._publisher.callRemote("subscribe", ca, service_name)
+        d.addBoth(self._debug_retired)
+        # We must also publish an empty 'stub_client' object, so the
+        # introducer can count how many clients are connected and see what
+        # versions they're running.
+        if not self._stub_client_furl:
+            self._stub_client = sc = StubClient()
+            self._stub_client_furl = self._tub.registerReference(sc)
+        def _publish_stub_client(ignored):
+            ri_name = RIStubClient.__remote_name__
+            self.publish(self._stub_client_furl, "stub_client", ri_name)
+        d.addCallback(_publish_stub_client)
+        return d
+
+    def create_announcement(self, furl, service_name, remoteinterface_name,
+                            signing_key=None):
+        ann_d = {"version": 0,
+                 "service-name": service_name,
+                 "FURL": furl,
+                 "remoteinterface-name": remoteinterface_name,
+
+                 "nickname": self._nickname,
+                 "app-versions": self._app_versions,
+                 "my-version": self._my_version,
+                 "oldest-supported": self._oldest_supported,
+                 }
+        return simplejson.dumps(sign(ann_d, signing_key))
+
+
+    def publish(self, furl, service_name, remoteinterface_name,
+                signing_key=None):
+        ann = self.create_announcement(furl, service_name, remoteinterface_name,
+                                       signing_key)
+        self._published_announcements[service_name] = ann
+        self._maybe_publish()
+
     def _maybe_publish(self):
         if not self._publisher:
             self.log("want to publish, but no introducer yet", level=log.NOISY)
             return
         # this re-publishes everything. The Introducer ignores duplicates
-        for ann in self._published_announcements:
+        for ann in self._published_announcements.values():
             self._debug_counts["outbound_message"] += 1
-            d = self._publisher.callRemote("publish", ann)
-            d.addErrback(trap_deadref)
-            d.addErrback(log.err,
-                         format="server errored during publish %(ann)s",
-                         ann=ann, facility="tahoe.introducer",
+            self._debug_outstanding += 1
+            d = self._publisher.callRemote("publish_v2", ann, self._canary)
+            d.addBoth(self._debug_retired)
+            d.addErrback(self._handle_v1_publisher, ann) # for_v1
+            d.addErrback(log.err, ann=ann, facility="tahoe.introducer.client",
                          level=log.WEIRD, umid="xs9pVQ")
 
-
-
-    def remote_announce(self, announcements):
-        self.log("received %d announcements" % len(announcements))
+    def _handle_v1_publisher(self, f, ann): # for_v1
+        f.trap(Violation, NameError)
+        # they don't have the 'publish_v2' method, so fall back to the old
+        # 'publish' method (which takes an unsigned tuple of bytestrings)
+        self.log("falling back to publish_v1",
+                 level=log.UNUSUAL, umid="9RCT1A", failure=f)
+        ann_v1 = convert_announcement_v2_to_v1(ann)
+        self._debug_outstanding += 1
+        d = self._publisher.callRemote("publish", ann_v1)
+        d.addBoth(self._debug_retired)
+        return d
+
+
+    def remote_announce_v2(self, announcements):
+        lp = self.log("received %d announcements (v2)" % len(announcements))
+        return self.got_announcements(announcements, lp)
+
+    def got_announcements(self, announcements, lp=None):
+        # this is the common entry point for both v1 and v2 announcements
         self._debug_counts["inbound_message"] += 1
-        for ann in announcements:
+        for ann_s in announcements:
             try:
-                self._process_announcement(ann)
-            except:
-                log.err(format="unable to process announcement %(ann)s",
-                        ann=ann)
-                # Don't let a corrupt announcement prevent us from processing
-                # the remaining ones. Don't return an error to the server,
-                # since they'd just ignore it anyways.
-                pass
-
-    def _process_announcement(self, ann):
+                ann_d, key = unsign(ann_s) # might raise bad-sig error
+            except BadSignatureError:
+                self.log("bad signature on inbound announcement: %s" % (ann_s,),
+                         parent=lp, level=log.WEIRD, umid="ZAU15Q")
+                # process other announcements that arrived with the bad one
+                continue
+
+            self._process_announcement(ann_d, key)
+
+    def _process_announcement(self, ann_d, key):
         self._debug_counts["inbound_announcement"] += 1
-        (furl, service_name, ri_name, nickname_utf8, ver, oldest) = ann
+        service_name = str(ann_d["service-name"])
         if service_name not in self._subscribed_service_names:
             self.log("announcement for a service we don't care about [%s]"
                      % (service_name,), level=log.UNUSUAL, umid="dIpGNA")
             self._debug_counts["wrong_service"] += 1
             return
-        self.log("announcement for [%s]: %s" % (service_name, ann),
-                 umid="BoKEag")
-        assert type(furl) is str
-        assert type(service_name) is str
-        assert type(ri_name) is str
-        assert type(nickname_utf8) is str
-        nickname = nickname_utf8.decode("utf-8")
-        assert type(nickname) is unicode
-        assert type(ver) is str
-        assert type(oldest) is str
-
-        nodeid = b32decode(SturdyRef(furl).tubID.upper())
-        nodeid_s = idlib.shortnodeid_b2a(nodeid)
-
-        ann_d = { "version": 0,
-                  "service-name": service_name,
-
-                  "FURL": furl,
-                  "nickname": nickname,
-                  "app-versions": {}, # need #466 and v2 introducer
-                  "my-version": ver,
-                  "oldest-supported": oldest,
-                  }
-
-        index = (service_name, nodeid)
-        if self._current_announcements.get(index, None) == ann_d:
-            self.log("reannouncement for [%(service)s]:%(nodeid)s, ignoring",
+        # for ASCII values, simplejson might give us unicode *or* bytes
+        if "nickname" in ann_d and isinstance(ann_d["nickname"], str):
+            ann_d["nickname"] = unicode(ann_d["nickname"])
+        nick_s = ann_d.get("nickname",u"").encode("utf-8")
+        lp2 = self.log(format="announcement for nickname '%(nick)s', service=%(svc)s: %(ann)s",
+                       nick=nick_s, svc=service_name, ann=ann_d, umid="BoKEag")
+
+        index = make_index(ann_d, key)
+        nodeid = index[1]
+        nodeid_s = idlib.nodeid_b2a(nodeid)
+
+        # is this announcement a duplicate?
+        if self._current_announcements.get(index, [None]*3)[0] == ann_d:
+            self.log(format="reannouncement for [%(service)s]:%(nodeid)s, ignoring",
                      service=service_name, nodeid=nodeid_s,
-                     level=log.UNUSUAL, umid="B1MIdA")
+                     parent=lp2, level=log.UNUSUAL, umid="B1MIdA")
             self._debug_counts["duplicate_announcement"] += 1
             return
+        # does it update an existing one?
         if index in self._current_announcements:
             self._debug_counts["update"] += 1
+            self.log("replacing old announcement: %s" % (ann_d,),
+                     parent=lp2, level=log.NOISY, umid="wxwgIQ")
         else:
             self._debug_counts["new_announcement"] += 1
+            self.log("new announcement[%s]" % service_name,
+                     parent=lp2, level=log.NOISY)
 
-        self._current_announcements[index] = ann_d
+        self._current_announcements[index] = (ann_d, key, time.time())
         # note: we never forget an index, but we might update its value
 
         for (service_name2,cb,args,kwargs) in self._local_subscribers:
diff --git a/src/allmydata/introducer/common.py b/src/allmydata/introducer/common.py
new file mode 100644
index 0000000..a057ecc
--- /dev/null
+++ b/src/allmydata/introducer/common.py
@@ -0,0 +1,72 @@
+
+import re, simplejson
+from base64 import b32decode
+from allmydata.util.ecdsa import VerifyingKey
+
+def make_index(ann_d, key):
+    """Return something that can be used as an index (e.g. a tuple of
+    strings), such that two messages that refer to the same 'thing' will have
+    the same index. For introducer announcements, this is a tuple of
+    (service-name, signing-key), or (service-name, tubid) if the announcement
+    is not signed."""
+
+    service_name = str(ann_d["service-name"])
+    if key:
+        index = (service_name, key.to_string())
+    else:
+        # otherwise, use the FURL to get a tubid
+        furl = str(ann_d["FURL"])
+        m = re.match(r'pb://(\w+)@', furl)
+        assert m
+        tubid = b32decode(m.group(1).upper())
+        index = (service_name, tubid)
+    return index
+
+def convert_announcement_v1_to_v2(ann_t):
+    (furl, service_name, ri_name, nickname, ver, oldest) = ann_t
+    assert type(furl) is str
+    assert type(service_name) is str
+    assert type(ri_name) is str
+    assert type(nickname) is str
+    assert type(ver) is str
+    assert type(oldest) is str
+    ann_d = {"version": 0,
+             "service-name": service_name,
+             "FURL": furl,
+             "remoteinterface-name": ri_name,
+
+             "nickname": nickname.decode("utf-8"),
+             "app-versions": {},
+             "my-version": ver,
+             "oldest-supported": oldest,
+             }
+    return simplejson.dumps( (simplejson.dumps(ann_d), None, None) )
+
+def convert_announcement_v2_to_v1(ann_v2):
+    (msg, sig, pubkey) = simplejson.loads(ann_v2)
+    ann_d = simplejson.loads(msg)
+    assert ann_d["version"] == 0
+    ann_t = (str(ann_d["FURL"]), str(ann_d["service-name"]),
+             str(ann_d["remoteinterface-name"]),
+             ann_d["nickname"].encode("utf-8"),
+             str(ann_d["my-version"]),
+             str(ann_d["oldest-supported"]),
+             )
+    return ann_t
+
+
+def sign(ann_d, sk):
+    msg = simplejson.dumps(ann_d)
+    if not sk:
+        return (msg, None, None)
+    vk = sk.get_verifying_key()
+    return (msg, sk.sign(msg).encode("hex"), vk.to_string().encode("hex"))
+
+def unsign(ann_s):
+    (msg_s, sig_s, key_s) = simplejson.loads(ann_s)
+    key = None
+    if sig_s and key_s:
+        key = VerifyingKey.from_string(key_s.decode("hex"))
+        key.verify(sig_s.decode("hex"), msg_s)
+    msg = simplejson.loads(msg_s)
+    return (msg, key)
diff --git a/src/allmydata/introducer/interfaces.py b/src/allmydata/introducer/interfaces.py
index 54f1701..03b0d9d 100644
--- a/src/allmydata/introducer/interfaces.py
+++ b/src/allmydata/introducer/interfaces.py
@@ -1,9 +1,12 @@
 
 from zope.interface import Interface
 from foolscap.api import StringConstraint, TupleOf, SetOf, DictOf, Any, \
-    RemoteInterface
+    RemoteInterface, Referenceable
+from old import RIIntroducerSubscriberClient_v1
 FURL = StringConstraint(1000)
 
+# old introducer protocol (v1):
+#
 # Announcements are (FURL, service_name, remoteinterface_name,
 #                    nickname, my_version, oldest_supported)
 #  the (FURL, service_name, remoteinterface_name) refer to the service being
@@ -14,13 +17,17 @@ FURL = StringConstraint(1000)
 #  incompatible peer. The second goal is to enable the development of
 #  backwards-compatibility code.
 
-Announcement = TupleOf(FURL, str, str,
-                       str, str, str)
+Announcement_v1 = TupleOf(FURL, str, str,
+                          str, str, str)
 
-class RIIntroducerSubscriberClient(RemoteInterface):
-    __remote_name__ = "RIIntroducerSubscriberClient.tahoe.allmydata.com"
+# new protocol: Announcements are strings, a JSON serialized 3-tuple of (msg,
+# sig, pubkey). More details to come.
+Announcement_v2 = str
 
-    def announce(announcements=SetOf(Announcement)):
+class RIIntroducerSubscriberClient_v2(RemoteInterface):
+    __remote_name__ = "RIIntroducerSubscriberClient_v2.tahoe.allmydata.com"
+
+    def announce_v2(announcements=SetOf(Announcement_v2)):
         """I accept announcements from the publisher."""
         return None
 
@@ -41,38 +48,29 @@ class RIIntroducerSubscriberClient(RemoteInterface):
         """
         return None
 
-# When Foolscap can handle multiple interfaces (Foolscap#17), the
-# full-powered introducer will implement both RIIntroducerPublisher and
-# RIIntroducerSubscriberService. Until then, we define
-# RIIntroducerPublisherAndSubscriberService as a combination of the two, and
-# make everybody use that.
+SubscriberInfo = DictOf(str, Any())
 
-class RIIntroducerPublisher(RemoteInterface):
+class RIIntroducerPublisherAndSubscriberService_v2(RemoteInterface):
     """To publish a service to the world, connect to me and give me your
-    announcement message. I will deliver a copy to all connected subscribers."""
-    __remote_name__ = "RIIntroducerPublisher.tahoe.allmydata.com"
-
-    def publish(announcement=Announcement):
-        # canary?
-        return None
-
-class RIIntroducerSubscriberService(RemoteInterface):
-    __remote_name__ = "RIIntroducerSubscriberService.tahoe.allmydata.com"
-
-    def subscribe(subscriber=RIIntroducerSubscriberClient, service_name=str):
-        """Give me a subscriber reference, and I will call its new_peers()
-        method will any announcements that match the desired service name. I
-        will ignore duplicate subscriptions.
-        """
-        return None
-
-class RIIntroducerPublisherAndSubscriberService(RemoteInterface):
-    __remote_name__ = "RIIntroducerPublisherAndSubscriberService.tahoe.allmydata.com"
+    announcement message. I will deliver a copy to all connected subscribers.
+    To hear about services, connect to me and subscribe to a specific
+    service_name."""
+    __remote_name__ = "RIIntroducerPublisherAndSubscriberService_v2.tahoe.allmydata.com"
     def get_version():
         return DictOf(str, Any())
-    def publish(announcement=Announcement):
+    def publish(announcement=Announcement_v1):
+        return None
+    def publish_v2(announcement=Announcement_v2, canary=Referenceable):
         return None
-    def subscribe(subscriber=RIIntroducerSubscriberClient, service_name=str):
+    def subscribe(subscriber=RIIntroducerSubscriberClient_v1, service_name=str):
+        return None
+    def subscribe_v2(subscriber=RIIntroducerSubscriberClient_v2,
+                     service_name=str, subscriber_info=SubscriberInfo):
+        """Give me a subscriber reference, and I will call its announce_v2()
+        method with any announcements that match the desired service name. I
+        will ignore duplicate subscriptions. The subscriber_info dictionary
+        tells me about the subscriber, and is used for diagnostic/status
+        displays."""
         return None
 
 class IIntroducerClient(Interface):
@@ -80,13 +78,17 @@ class IIntroducerClient(Interface):
     publish their services to the rest of the world, and I help them learn
     about services available on other nodes."""
 
-    def publish(furl, service_name, remoteinterface_name):
+    def publish(furl, service_name, remoteinterface_name,
+                signing_key=None):
         """Once you call this, I will tell the world that the Referenceable
         available at FURL is available to provide a service named
         SERVICE_NAME. The precise definition of the service being provided is
         identified by the Foolscap 'remote interface name' in the last
         parameter: this is supposed to be a globally-unique string that
-        identifies the RemoteInterface that is implemented."""
+        identifies the RemoteInterface that is implemented.
+
+        If signing_key= is set to an instance of ecdsa.SigningKey, it will be
+        used to sign the announcement."""
 
     def subscribe_to(service_name, callback, *args, **kwargs):
         """Call this if you will eventually want to use services with the
diff --git a/src/allmydata/introducer/old.py b/src/allmydata/introducer/old.py
new file mode 100644
index 0000000..e0bdacf
--- /dev/null
+++ b/src/allmydata/introducer/old.py
@@ -0,0 +1,463 @@
+
+import time
+from base64 import b32decode
+from zope.interface import implements, Interface
+from twisted.application import service
+import allmydata
+from allmydata.interfaces import InsufficientVersionError
+from allmydata.util import log, idlib, rrefutil
+from foolscap.api import StringConstraint, TupleOf, SetOf, DictOf, Any, \
+    RemoteInterface, Referenceable, eventually, SturdyRef
+FURL = StringConstraint(1000)
+
+# We keep a copy of the old introducer (both client and server) here to
+# support compatibility tests. The old client is supposed to handle the new
+# server, and new client is supposed to handle the old server.
+
+
+# Announcements are (FURL, service_name, remoteinterface_name,
+#                    nickname, my_version, oldest_supported)
+#  the (FURL, service_name, remoteinterface_name) refer to the service being
+#  announced. The (nickname, my_version, oldest_supported) refer to the
+#  client as a whole. The my_version/oldest_supported strings can be parsed
+#  by an allmydata.util.version.Version instance, and then compared. The
+#  first goal is to make sure that nodes are not confused by speaking to an
+#  incompatible peer. The second goal is to enable the development of
+#  backwards-compatibility code.
+
+Announcement = TupleOf(FURL, str, str,
+                       str, str, str)
+
+class RIIntroducerSubscriberClient_v1(RemoteInterface):
+    __remote_name__ = "RIIntroducerSubscriberClient.tahoe.allmydata.com"
+
+    def announce(announcements=SetOf(Announcement)):
+        """I accept announcements from the publisher."""
+        return None
+
+    def set_encoding_parameters(parameters=(int, int, int)):
+        """Advise the client of the recommended k-of-n encoding parameters
+        for this grid. 'parameters' is a tuple of (k, desired, n), where 'n'
+        is the total number of shares that will be created for any given
+        file, while 'k' is the number of shares that must be retrieved to
+        recover that file, and 'desired' is the minimum number of shares that
+        must be placed before the uploader will consider its job a success.
+        n/k is the expansion ratio, while k determines the robustness.
+
+        Introducers should specify 'n' according to the expected size of the
+        grid (there is no point to producing more shares than there are
+        peers), and k according to the desired reliability-vs-overhead goals.
+
+        Note that setting k=1 is equivalent to simple replication.
+        """
+        return None
+
+# When Foolscap can handle multiple interfaces (Foolscap#17), the
+# full-powered introducer will implement both RIIntroducerPublisher and
+# RIIntroducerSubscriberService. Until then, we define
+# RIIntroducerPublisherAndSubscriberService as a combination of the two, and
+# make everybody use that.
+
+class RIIntroducerPublisher_v1(RemoteInterface):
+    """To publish a service to the world, connect to me and give me your
+    announcement message. I will deliver a copy to all connected subscribers."""
+    __remote_name__ = "RIIntroducerPublisher.tahoe.allmydata.com"
+
+    def publish(announcement=Announcement):
+        # canary?
+        return None
+
+class RIIntroducerSubscriberService_v1(RemoteInterface):
+    __remote_name__ = "RIIntroducerSubscriberService.tahoe.allmydata.com"
+
+    def subscribe(subscriber=RIIntroducerSubscriberClient_v1, service_name=str):
+        """Give me a subscriber reference, and I will call its new_peers()
+        method will any announcements that match the desired service name. I
+        will ignore duplicate subscriptions.
+        """
+        return None
+
+class RIIntroducerPublisherAndSubscriberService_v1(RemoteInterface):
+    __remote_name__ = "RIIntroducerPublisherAndSubscriberService.tahoe.allmydata.com"
+    def get_version():
+        return DictOf(str, Any())
+    def publish(announcement=Announcement):
+        return None
+    def subscribe(subscriber=RIIntroducerSubscriberClient_v1, service_name=str):
+        return None
+
+class IIntroducerClient(Interface):
+    """I provide service introduction facilities for a node. I help nodes
+    publish their services to the rest of the world, and I help them learn
+    about services available on other nodes."""
+
+    def publish(furl, service_name, remoteinterface_name):
+        """Once you call this, I will tell the world that the Referenceable
+        available at FURL is available to provide a service named
+        SERVICE_NAME. The precise definition of the service being provided is
+        identified by the Foolscap 'remote interface name' in the last
+        parameter: this is supposed to be a globally-unique string that
+        identifies the RemoteInterface that is implemented."""
+
+    def subscribe_to(service_name, callback, *args, **kwargs):
+        """Call this if you will eventually want to use services with the
+        given SERVICE_NAME. This will prompt me to subscribe to announcements
+        of those services. Your callback will be invoked with at least two
+        arguments: a serverid (binary string), and an announcement
+        dictionary, followed by any additional callback args/kwargs you give
+        me. I will run your callback for both new announcements and for
+        announcements that have changed, but you must be prepared to tolerate
+        duplicates.
+
+        The announcement dictionary that I give you will have the following
+        keys:
+
+         version: 0
+         service-name: str('storage')
+
+         FURL: str(furl)
+         remoteinterface-name: str(ri_name)
+         nickname: unicode
+         app-versions: {}
+         my-version: str
+         oldest-supported: str
+
+        Note that app-version will be an empty dictionary until #466 is done
+        and both the introducer and the remote client have been upgraded. For
+        current (native) server types, the serverid will always be equal to
+        the binary form of the FURL's tubid.
+        """
+
+    def connected_to_introducer():
+        """Returns a boolean, True if we are currently connected to the
+        introducer, False if not."""
+
+
+class IntroducerClient_v1(service.Service, Referenceable):
+    implements(RIIntroducerSubscriberClient_v1, IIntroducerClient)
+
+    def __init__(self, tub, introducer_furl,
+                 nickname, my_version, oldest_supported):
+        self._tub = tub
+        self.introducer_furl = introducer_furl
+
+        assert type(nickname) is unicode
+        self._nickname_utf8 = nickname.encode("utf-8") # we always send UTF-8
+        self._my_version = my_version
+        self._oldest_supported = oldest_supported
+
+        self._published_announcements = set()
+
+        self._publisher = None
+
+        self._local_subscribers = [] # (servicename,cb,args,kwargs) tuples
+        self._subscribed_service_names = set()
+        self._subscriptions = set() # requests we've actually sent
+
+        # _current_announcements remembers one announcement per
+        # (servicename,serverid) pair. Anything that arrives with the same
+        # pair will displace the previous one. This stores unpacked
+        # announcement dictionaries, which can be compared for equality to
+        # distinguish re-announcement from updates. It also provides memory
+        # for clients who subscribe after startup.
+        self._current_announcements = {}
+
+        self.encoding_parameters = None
+
+        # hooks for unit tests
+        self._debug_counts = {
+            "inbound_message": 0,
+            "inbound_announcement": 0,
+            "wrong_service": 0,
+            "duplicate_announcement": 0,
+            "update": 0,
+            "new_announcement": 0,
+            "outbound_message": 0,
+            }
+        self._debug_outstanding = 0
+
+    def _debug_retired(self, res):
+        self._debug_outstanding -= 1
+        return res
+
+    def startService(self):
+        service.Service.startService(self)
+        self._introducer_error = None
+        rc = self._tub.connectTo(self.introducer_furl, self._got_introducer)
+        self._introducer_reconnector = rc
+        def connect_failed(failure):
+            self.log("Initial Introducer connection failed: perhaps it's down",
+                     level=log.WEIRD, failure=failure, umid="c5MqUQ")
+        d = self._tub.getReference(self.introducer_furl)
+        d.addErrback(connect_failed)
+
+    def _got_introducer(self, publisher):
+        self.log("connected to introducer, getting versions")
+        default = { "http://allmydata.org/tahoe/protocols/introducer/v1":
+                    { },
+                    "application-version": "unknown: no get_version()",
+                    }
+        d = rrefutil.add_version_to_remote_reference(publisher, default)
+        d.addCallback(self._got_versioned_introducer)
+        d.addErrback(self._got_error)
+
+    def _got_error(self, f):
+        # TODO: for the introducer, perhaps this should halt the application
+        self._introducer_error = f # polled by tests
+
+    def _got_versioned_introducer(self, publisher):
+        self.log("got introducer version: %s" % (publisher.version,))
+        # we require a V1 introducer
+        needed = "http://allmydata.org/tahoe/protocols/introducer/v1"
+        if needed not in publisher.version:
+            raise InsufficientVersionError(needed, publisher.version)
+        self._publisher = publisher
+        publisher.notifyOnDisconnect(self._disconnected)
+        self._maybe_publish()
+        self._maybe_subscribe()
+
+    def _disconnected(self):
+        self.log("bummer, we've lost our connection to the introducer")
+        self._publisher = None
+        self._subscriptions.clear()
+
+    def log(self, *args, **kwargs):
+        if "facility" not in kwargs:
+            kwargs["facility"] = "tahoe.introducer"
+        return log.msg(*args, **kwargs)
+
+
+    def publish(self, furl, service_name, remoteinterface_name):
+        assert type(self._nickname_utf8) is str # we always send UTF-8
+        ann = (furl, service_name, remoteinterface_name,
+               self._nickname_utf8, self._my_version, self._oldest_supported)
+        self._published_announcements.add(ann)
+        self._maybe_publish()
+
+    def subscribe_to(self, service_name, cb, *args, **kwargs):
+        self._local_subscribers.append( (service_name,cb,args,kwargs) )
+        self._subscribed_service_names.add(service_name)
+        self._maybe_subscribe()
+        for (servicename,nodeid),ann_d in self._current_announcements.items():
+            if servicename == service_name:
+                eventually(cb, nodeid, ann_d)
+
+    def _maybe_subscribe(self):
+        if not self._publisher:
+            self.log("want to subscribe, but no introducer yet",
+                     level=log.NOISY)
+            return
+        for service_name in self._subscribed_service_names:
+            if service_name not in self._subscriptions:
+                # there is a race here, but the subscription desk ignores
+                # duplicate requests.
+                self._subscriptions.add(service_name)
+                self._debug_outstanding += 1
+                d = self._publisher.callRemote("subscribe", self, service_name)
+                d.addBoth(self._debug_retired)
+                d.addErrback(rrefutil.trap_deadref)
+                d.addErrback(log.err, format="server errored during subscribe",
+                             facility="tahoe.introducer",
+                             level=log.WEIRD, umid="2uMScQ")
+
+    def _maybe_publish(self):
+        if not self._publisher:
+            self.log("want to publish, but no introducer yet", level=log.NOISY)
+            return
+        # this re-publishes everything. The Introducer ignores duplicates
+        for ann in self._published_announcements:
+            self._debug_counts["outbound_message"] += 1
+            self._debug_outstanding += 1
+            d = self._publisher.callRemote("publish", ann)
+            d.addBoth(self._debug_retired)
+            d.addErrback(rrefutil.trap_deadref)
+            d.addErrback(log.err,
+                         format="server errored during publish %(ann)s",
+                         ann=ann, facility="tahoe.introducer",
+                         level=log.WEIRD, umid="xs9pVQ")
+
+
+
+    def remote_announce(self, announcements):
+        self.log("received %d announcements" % len(announcements))
+        self._debug_counts["inbound_message"] += 1
+        for ann in announcements:
+            try:
+                self._process_announcement(ann)
+            except:
+                log.err(format="unable to process announcement %(ann)s",
+                        ann=ann)
+                # Don't let a corrupt announcement prevent us from processing
+                # the remaining ones. Don't return an error to the server,
+                # since they'd just ignore it anyways.
+                pass
+
+    def _process_announcement(self, ann):
+        self._debug_counts["inbound_announcement"] += 1
+        (furl, service_name, ri_name, nickname_utf8, ver, oldest) = ann
+        if service_name not in self._subscribed_service_names:
+            self.log("announcement for a service we don't care about [%s]"
+                     % (service_name,), level=log.UNUSUAL, umid="dIpGNA")
+            self._debug_counts["wrong_service"] += 1
+            return
+        self.log("announcement for [%s]: %s" % (service_name, ann),
+                 umid="BoKEag")
+        assert type(furl) is str
+        assert type(service_name) is str
+        assert type(ri_name) is str
+        assert type(nickname_utf8) is str
+        nickname = nickname_utf8.decode("utf-8")
+        assert type(nickname) is unicode
+        assert type(ver) is str
+        assert type(oldest) is str
+
+        nodeid = b32decode(SturdyRef(furl).tubID.upper())
+        nodeid_s = idlib.shortnodeid_b2a(nodeid)
+
+        ann_d = { "version": 0,
+                  "service-name": service_name,
+
+                  "FURL": furl,
+                  "nickname": nickname,
+                  "app-versions": {}, # need #466 and v2 introducer
+                  "my-version": ver,
+                  "oldest-supported": oldest,
+                  }
+
+        index = (service_name, nodeid)
+        if self._current_announcements.get(index, None) == ann_d:
+            self.log("reannouncement for [%(service)s]:%(nodeid)s, ignoring",
+                     service=service_name, nodeid=nodeid_s,
+                     level=log.UNUSUAL, umid="B1MIdA")
+            self._debug_counts["duplicate_announcement"] += 1
+            return
+        if index in self._current_announcements:
+            self._debug_counts["update"] += 1
+        else:
+            self._debug_counts["new_announcement"] += 1
+
+        self._current_announcements[index] = ann_d
+        # note: we never forget an index, but we might update its value
+
+        for (service_name2,cb,args,kwargs) in self._local_subscribers:
+            if service_name2 == service_name:
+                eventually(cb, nodeid, ann_d, *args, **kwargs)
+
+    def remote_set_encoding_parameters(self, parameters):
+        self.encoding_parameters = parameters
+
+    def connected_to_introducer(self):
+        return bool(self._publisher)
+
+class IntroducerService_v1(service.MultiService, Referenceable):
+    implements(RIIntroducerPublisherAndSubscriberService_v1)
+    name = "introducer"
+    VERSION = { "http://allmydata.org/tahoe/protocols/introducer/v1":
+                 { },
+                "application-version": str(allmydata.__full_version__),
+                }
+
+    def __init__(self, basedir="."):
+        service.MultiService.__init__(self)
+        self.introducer_url = None
+        # 'index' is (service_name, tubid)
+        self._announcements = {} # dict of index -> (announcement, timestamp)
+        self._subscribers = {} # dict of (rref->timestamp) dicts
+        self._debug_counts = {"inbound_message": 0,
+                              "inbound_duplicate": 0,
+                              "inbound_update": 0,
+                              "outbound_message": 0,
+                              "outbound_announcements": 0,
+                              "inbound_subscribe": 0}
+        self._debug_outstanding = 0
+
+    def _debug_retired(self, res):
+        self._debug_outstanding -= 1
+        return res
+
+    def log(self, *args, **kwargs):
+        if "facility" not in kwargs:
+            kwargs["facility"] = "tahoe.introducer"
+        return log.msg(*args, **kwargs)
+
+    def get_announcements(self):
+        return self._announcements
+    def get_subscribers(self):
+        return self._subscribers
+
+    def remote_get_version(self):
+        return self.VERSION
+
+    def remote_publish(self, announcement):
+        try:
+            self._publish(announcement)
+        except:
+            log.err(format="Introducer.remote_publish failed on %(ann)s",
+                    ann=announcement, level=log.UNUSUAL, umid="620rWA")
+            raise
+
+    def _publish(self, announcement):
+        self._debug_counts["inbound_message"] += 1
+        self.log("introducer: announcement published: %s" % (announcement,) )
+        (furl, service_name, ri_name, nickname_utf8, ver, oldest) = announcement
+        #print "PUB", service_name, nickname_utf8
+
+        nodeid = b32decode(SturdyRef(furl).tubID.upper())
+        index = (service_name, nodeid)
+
+        if index in self._announcements:
+            (old_announcement, timestamp) = self._announcements[index]
+            if old_announcement == announcement:
+                self.log("but we already knew it, ignoring", level=log.NOISY)
+                self._debug_counts["inbound_duplicate"] += 1
+                return
+            else:
+                self.log("old announcement being updated", level=log.NOISY)
+                self._debug_counts["inbound_update"] += 1
+        self._announcements[index] = (announcement, time.time())
+
+        for s in self._subscribers.get(service_name, []):
+            self._debug_counts["outbound_message"] += 1
+            self._debug_counts["outbound_announcements"] += 1
+            self._debug_outstanding += 1
+            d = s.callRemote("announce", set([announcement]))
+            d.addBoth(self._debug_retired)
+            d.addErrback(rrefutil.trap_deadref)
+            d.addErrback(log.err,
+                         format="subscriber errored on announcement %(ann)s",
+                         ann=announcement, facility="tahoe.introducer",
+                         level=log.UNUSUAL, umid="jfGMXQ")
+
+    def remote_subscribe(self, subscriber, service_name):
+        self.log("introducer: subscription[%s] request at %s" % (service_name,
+                                                                 subscriber))
+        self._debug_counts["inbound_subscribe"] += 1
+        if service_name not in self._subscribers:
+            self._subscribers[service_name] = {}
+        subscribers = self._subscribers[service_name]
+        if subscriber in subscribers:
+            self.log("but they're already subscribed, ignoring",
+                     level=log.UNUSUAL)
+            return
+        subscribers[subscriber] = time.time()
+        def _remove():
+            self.log("introducer: unsubscribing[%s] %s" % (service_name,
+                                                           subscriber))
+            subscribers.pop(subscriber, None)
+        subscriber.notifyOnDisconnect(_remove)
+
+        announcements = set(
+            [ ann
+              for (sn2,nodeid),(ann,when) in self._announcements.items()
+              if sn2 == service_name] )
+
+        self._debug_counts["outbound_message"] += 1
+        self._debug_counts["outbound_announcements"] += len(announcements)
+        self._debug_outstanding += 1
+        d = subscriber.callRemote("announce", announcements)
+        d.addBoth(self._debug_retired)
+        d.addErrback(rrefutil.trap_deadref)
+        d.addErrback(log.err,
+                     format="subscriber errored during subscribe %(anns)s",
+                     anns=announcements, facility="tahoe.introducer",
+                     level=log.UNUSUAL, umid="1XChxA")
diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index 117fcb5..7868e8f 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -1,14 +1,15 @@
 
 import time, os.path
-from base64 import b32decode
 from zope.interface import implements
 from twisted.application import service
-from foolscap.api import Referenceable, SturdyRef
+from foolscap.api import Referenceable
 import allmydata
 from allmydata import node
-from allmydata.util import log, rrefutil
+from allmydata.util import log, base32, idlib
 from allmydata.introducer.interfaces import \
-     RIIntroducerPublisherAndSubscriberService
+     RIIntroducerPublisherAndSubscriberService_v2
+from allmydata.introducer.common import convert_announcement_v1_to_v2, \
+     convert_announcement_v2_to_v1, unsign, make_index
 
 class IntroducerNode(node.Node):
     PORTNUMFILE = "introducer.port"
@@ -30,22 +31,53 @@ class IntroducerNode(node.Node):
         def _publish(res):
             self.introducer_url = self.tub.registerReference(introducerservice,
                                                              "introducer")
-            self.log(" introducer is at %s" % self.introducer_url)
+            self.log(" introducer is at %s" % self.introducer_url,
+                     umid="qF2L9A")
             self.write_config("introducer.furl", self.introducer_url + "\n")
         d.addCallback(_publish)
         d.addErrback(log.err, facility="tahoe.init",
                      level=log.BAD, umid="UaNs9A")
 
     def init_web(self, webport):
-        self.log("init_web(webport=%s)", args=(webport,))
+        self.log("init_web(webport=%s)", args=(webport,), umid="2bUygA")
 
         from allmydata.webish import IntroducerWebishServer
         nodeurl_path = os.path.join(self.basedir, "node.url")
         ws = IntroducerWebishServer(self, webport, nodeurl_path)
         self.add_service(ws)
 
+class SubscriberAdapter_v1: # for_v1
+    """I wrap a RemoteReference that points at an old v1 subscriber, enabling
+    it to be treated like a v2 subscriber.
+    """
+
+    def __init__(self, original):
+        self.original = original
+    def __eq__(self, them):
+        return self.original == them
+    def __ne__(self, them):
+        return self.original != them
+    def __hash__(self):
+        return hash(self.original)
+    def getRemoteTubID(self):
+        return self.original.getRemoteTubID()
+    def getSturdyRef(self):
+        return self.original.getSturdyRef()
+    def getPeer(self):
+        return self.original.getPeer()
+    def callRemote(self, methname, *args, **kwargs):
+        m = getattr(self, "wrap_" + methname)
+        return m(*args, **kwargs)
+    def wrap_announce_v2(self, announcements):
+        anns_v1 = [convert_announcement_v2_to_v1(ann) for ann in announcements]
+        return self.original.callRemote("announce", set(anns_v1))
+    def wrap_set_encoding_parameters(self, parameters):
+        return self.original.callRemote("set_encoding_parameters", parameters)
+    def notifyOnDisconnect(self, *args, **kwargs):
+        return self.original.notifyOnDisconnect(*args, **kwargs)
+
 class IntroducerService(service.MultiService, Referenceable):
-    implements(RIIntroducerPublisherAndSubscriberService)
+    implements(RIIntroducerPublisherAndSubscriberService_v2)
     name = "introducer"
     VERSION = { "http://allmydata.org/tahoe/protocols/introducer/v1":
                  { },
@@ -56,93 +88,214 @@ class IntroducerService(service.MultiService, Referenceable):
         service.MultiService.__init__(self)
         self.introducer_url = None
         # 'index' is (service_name, tubid)
-        self._announcements = {} # dict of index -> (announcement, timestamp)
-        self._subscribers = {} # dict of (rref->timestamp) dicts
+        self._announcements = {} # dict of index ->
+                                 # (ann_s, canary, ann_d, timestamp)
+
+        # ann_d is cleaned up (nickname is always unicode, servicename is
+        # always ascii, etc, even though simplejson.loads sometimes returns
+        # either)
+
+        # self._subscribers is a dict mapping servicename to subscriptions
+        # 'subscriptions' is a dict mapping rref to a subscription
+        # 'subscription' is a tuple of (subscriber_info, timestamp)
+        # 'subscriber_info' is a dict, provided directly for v2 clients, or
+        # synthesized for v1 clients. The expected keys are:
+        #  version, nickname, app-versions, my-version, oldest-supported
+        self._subscribers = {}
+
+        # self._stub_client_announcements contains the information provided
+        # by v1 clients. We stash this so we can match it up with their
+        # subscriptions.
+        self._stub_client_announcements = {} # maps tubid to sinfo # for_v1
+
         self._debug_counts = {"inbound_message": 0,
                               "inbound_duplicate": 0,
                               "inbound_update": 0,
                               "outbound_message": 0,
                               "outbound_announcements": 0,
                               "inbound_subscribe": 0}
+        self._debug_outstanding = 0 # also covers SubscriberAdapter_v1
+
+    def _debug_retired(self, res):
+        self._debug_outstanding -= 1
+        return res
 
     def log(self, *args, **kwargs):
         if "facility" not in kwargs:
-            kwargs["facility"] = "tahoe.introducer"
+            kwargs["facility"] = "tahoe.introducer.server"
         return log.msg(*args, **kwargs)
 
     def get_announcements(self):
         return self._announcements
     def get_subscribers(self):
-        return self._subscribers
+        """Return a list of (service_name, when, subscriber_info, rref) for
+        all subscribers. subscriber_info is a dict with the following keys:
+        version, nickname, app-versions, my-version, oldest-supported"""
+        s = []
+        for service_name, subscriptions in self._subscribers.items():
+            for rref,(subscriber_info,when) in subscriptions.items():
+                s.append( (service_name, when, subscriber_info, rref) )
+        return s
 
     def remote_get_version(self):
         return self.VERSION
 
-    def remote_publish(self, announcement):
+    def remote_publish(self, ann_s): # for_v1
+        lp = self.log("introducer: old (v1) announcement published: %s"
+                      % (ann_s,), umid="6zGOIw")
+        ann_v2 = convert_announcement_v1_to_v2(ann_s)
+        return self.publish(ann_v2, None, lp)
+
+    def remote_publish_v2(self, ann_s, canary):
+        lp = self.log("introducer: announcement (v2) published", umid="L2QXkQ")
+        return self.publish(ann_s, canary, lp)
+
+    def publish(self, ann_s, canary, lp):
         try:
-            self._publish(announcement)
+            self._publish(ann_s, canary, lp)
         except:
             log.err(format="Introducer.remote_publish failed on %(ann)s",
-                    ann=announcement, level=log.UNUSUAL, umid="620rWA")
+                    ann=ann_s,
+                    level=log.UNUSUAL, parent=lp, umid="620rWA")
             raise
 
-    def _publish(self, announcement):
+    def _publish(self, ann_s, canary, lp):
         self._debug_counts["inbound_message"] += 1
-        self.log("introducer: announcement published: %s" % (announcement,) )
-        (furl, service_name, ri_name, nickname_utf8, ver, oldest) = announcement
+        self.log("introducer: announcement published: %s" % (ann_s,),
+                 umid="wKHgCw")
+        ann_d, key = unsign(ann_s) # might raise BadSignatureError
+        index = make_index(ann_d, key)
 
-        nodeid = b32decode(SturdyRef(furl).tubID.upper())
-        index = (service_name, nodeid)
+        service_name = str(ann_d["service-name"])
+        if service_name == "stub_client": # for_v1
+            self._attach_stub_client(ann_d, index, lp)
+            return
 
         if index in self._announcements:
-            (old_announcement, timestamp) = self._announcements[index]
-            if old_announcement == announcement:
-                self.log("but we already knew it, ignoring", level=log.NOISY)
+            (old_ann_s, canary, ann_d, timestamp) = self._announcements[index]
+            if old_ann_s == ann_s:
+                self.log("but we already knew it, ignoring", level=log.NOISY,
+                         umid="myxzLw")
                 self._debug_counts["inbound_duplicate"] += 1
                 return
             else:
-                self.log("old announcement being updated", level=log.NOISY)
+                self.log("old announcement being updated", level=log.NOISY,
+                         umid="304r9g")
                 self._debug_counts["inbound_update"] += 1
-        self._announcements[index] = (announcement, time.time())
+        self._announcements[index] = (ann_s, canary, ann_d, time.time())
+        #if canary:
+        #    canary.notifyOnDisconnect ...
+        # use a CanaryWatcher? with cw.is_connected()?
+        # actually we just want foolscap to give rref.is_connected(), since
+        # this is only for the status display
 
         for s in self._subscribers.get(service_name, []):
             self._debug_counts["outbound_message"] += 1
             self._debug_counts["outbound_announcements"] += 1
-            d = s.callRemote("announce", set([announcement]))
-            d.addErrback(rrefutil.trap_deadref)
+            self._debug_outstanding += 1
+            d = s.callRemote("announce_v2", set([ann_s]))
+            d.addBoth(self._debug_retired)
             d.addErrback(log.err,
                          format="subscriber errored on announcement %(ann)s",
-                         ann=announcement, facility="tahoe.introducer",
+                         ann=ann_s, facility="tahoe.introducer",
                          level=log.UNUSUAL, umid="jfGMXQ")
 
-    def remote_subscribe(self, subscriber, service_name):
-        self.log("introducer: subscription[%s] request at %s" % (service_name,
-                                                                 subscriber))
+    def _attach_stub_client(self, ann_d, index, lp):
+        # There might be a v1 subscriber for whom this is a stub_client.
+        # We might have received the subscription before the stub_client
+        # announcement, in which case we now need to fix up the record in
+        # self._subscriptions .
+
+        # record it for later, in case the stub_client arrived before the
+        # subscription
+        subscriber_info = self._get_subscriber_info_from_ann_d(ann_d)
+        ann_tubid = index[1]
+        self._stub_client_announcements[ann_tubid] = subscriber_info
+
+        lp2 = self.log("stub_client announcement, "
+                       "looking for matching subscriber",
+                       parent=lp, level=log.NOISY, umid="BTywDg")
+
+        for sn in self._subscribers:
+            s = self._subscribers[sn]
+            for (subscriber, info) in s.items():
+                # we correlate these by looking for a subscriber whose tubid
+                # matches this announcement
+                sub_tubid = base32.a2b(subscriber.getRemoteTubID()) # binary
+                if sub_tubid == ann_tubid:
+                    self.log(format="found a match, nodeid=%(nodeid)s",
+                             nodeid=idlib.nodeid_b2a(sub_tubid),
+                             level=log.NOISY, parent=lp2, umid="xsWs1A")
+                    # found a match. Does it need info?
+                    if not info[0]:
+                        self.log(format="replacing info",
+                                 level=log.NOISY, parent=lp2, umid="m5kxwA")
+                        # yup
+                        s[subscriber] = (subscriber_info, info[1])
+            # and we don't remember or announce stub_clients beyond what we
+            # need to get the subscriber_info set up
+
+    def _get_subscriber_info_from_ann_d(self, ann_d): # for_v1
+        sinfo = { "version": ann_d["version"],
+                  "nickname": ann_d["nickname"],
+                  "app-versions": ann_d["app-versions"],
+                  "my-version": ann_d["my-version"],
+                  "oldest-supported": ann_d["oldest-supported"],
+                  }
+        return sinfo
+
+    def remote_subscribe(self, subscriber, service_name): # for_v1
+        self.log("introducer: old (v1) subscription[%s] request at %s"
+                 % (service_name, subscriber), umid="hJlGUg")
+        return self.add_subscriber(SubscriberAdapter_v1(subscriber),
+                                   service_name, None)
+
+    def remote_subscribe_v2(self, subscriber, service_name, subscriber_info):
+        self.log("introducer: subscription[%s] request at %s"
+                 % (service_name, subscriber), umid="U3uzLg")
+        return self.add_subscriber(subscriber, service_name, subscriber_info)
+
+    def add_subscriber(self, subscriber, service_name, subscriber_info):
         self._debug_counts["inbound_subscribe"] += 1
         if service_name not in self._subscribers:
             self._subscribers[service_name] = {}
         subscribers = self._subscribers[service_name]
         if subscriber in subscribers:
             self.log("but they're already subscribed, ignoring",
-                     level=log.UNUSUAL)
+                     level=log.UNUSUAL, umid="Sy9EfA")
             return
-        subscribers[subscriber] = time.time()
+
+        if not subscriber_info: # for_v1
+            # v1 clients don't provide subscriber_info, but they should
+            # publish a 'stub client' record which contains the same
+            # information. If we've already received this, it will be in
+            # self._stub_client_announcements
+            tubid_b32 = subscriber.getRemoteTubID()
+            tubid = base32.a2b(tubid_b32)
+            if tubid in self._stub_client_announcements:
+                subscriber_info = self._stub_client_announcements[tubid]
+
+        subscribers[subscriber] = (subscriber_info, time.time())
         def _remove():
             self.log("introducer: unsubscribing[%s] %s" % (service_name,
-                                                           subscriber))
+                                                           subscriber),
+                     umid="vYGcJg")
             subscribers.pop(subscriber, None)
         subscriber.notifyOnDisconnect(_remove)
 
-        announcements = set(
-            [ ann
-              for (sn2,nodeid),(ann,when) in self._announcements.items()
-              if sn2 == service_name] )
-
-        self._debug_counts["outbound_message"] += 1
-        self._debug_counts["outbound_announcements"] += len(announcements)
-        d = subscriber.callRemote("announce", announcements)
-        d.addErrback(rrefutil.trap_deadref)
-        d.addErrback(log.err,
-                     format="subscriber errored during subscribe %(anns)s",
-                     anns=announcements, facility="tahoe.introducer",
-                     level=log.UNUSUAL, umid="mtZepQ")
+        # now tell them about any announcements they're interested in
+        announcements = set( [ ann_s
+                               for idx,(ann_s,canary,ann_d,when)
+                               in self._announcements.items()
+                               if idx[0] == service_name] )
+        if announcements:
+            self._debug_counts["outbound_message"] += 1
+            self._debug_counts["outbound_announcements"] += len(announcements)
+            self._debug_outstanding += 1
+            d = subscriber.callRemote("announce_v2", announcements)
+            d.addBoth(self._debug_retired)
+            d.addErrback(log.err,
+                         format="subscriber errored during subscribe %(anns)s",
+                         anns=announcements, facility="tahoe.introducer",
+                         level=log.UNUSUAL, umid="mtZepQ")
+            return d
diff --git a/src/allmydata/test/test_introducer.py b/src/allmydata/test/test_introducer.py
index 9d0f50e..69d7f1d 100644
--- a/src/allmydata/test/test_introducer.py
+++ b/src/allmydata/test/test_introducer.py
@@ -9,11 +9,12 @@ from twisted.python import log
 from foolscap.api import Tub, Referenceable, fireEventually, flushEventualQueue
 from twisted.application import service
 from allmydata.interfaces import InsufficientVersionError
-from allmydata.introducer.client import IntroducerClient
+from allmydata.introducer.client import IntroducerClient, ClientAdapter_v1
 from allmydata.introducer.server import IntroducerService
+from allmydata.introducer import old
 # test compatibility with old introducer .tac files
 from allmydata.introducer import IntroducerNode
-from allmydata.util import pollmixin
+from allmydata.util import pollmixin, ecdsa
 import allmydata.test.common_util as testutil
 
 class LoggingMultiService(service.MultiService):
@@ -47,14 +48,14 @@ class Introducer(ServiceMixin, unittest.TestCase, pollmixin.PollMixin):
 
     def test_create(self):
         ic = IntroducerClient(None, "introducer.furl", u"my_nickname",
-                              "my_version", "oldest_version")
+                              "my_version", "oldest_version", {})
         self.failUnless(isinstance(ic, IntroducerClient))
 
     def test_listen(self):
         i = IntroducerService()
         i.setServiceParent(self.parent)
 
-    def test_duplicate(self):
+    def test_duplicate_publish(self):
         i = IntroducerService()
         self.failUnlessEqual(len(i.get_announcements()), 0)
         self.failUnlessEqual(len(i.get_subscribers()), 0)
@@ -73,6 +74,152 @@ class Introducer(ServiceMixin, unittest.TestCase, pollmixin.PollMixin):
         self.failUnlessEqual(len(i.get_announcements()), 2)
         self.failUnlessEqual(len(i.get_subscribers()), 0)
 
+
+
+class Client(unittest.TestCase):
+    def test_duplicate_receive_v1(self):
+        ic = IntroducerClient(None,
+                              "introducer.furl", u"my_nickname",
+                              "my_version", "oldest_version", {})
+        announcements = []
+        ic.subscribe_to("storage",
+                        lambda nodeid,ann_d: announcements.append(ann_d))
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:36106/gydnpigj2ja2qr2srq4ikjwnl7xfgbra"
+        ann1 = (furl1, "storage", "RIStorage", "nick1", "ver23", "ver0")
+        ann1b = (furl1, "storage", "RIStorage", "nick1", "ver24", "ver0")
+        ca = ClientAdapter_v1(ic)
+
+        ca.remote_announce([ann1])
+        d = fireEventually()
+        def _then(ign):
+            self.failUnlessEqual(len(announcements), 1)
+            self.failUnlessEqual(announcements[0]["nickname"], u"nick1")
+            self.failUnlessEqual(announcements[0]["my-version"], "ver23")
+            self.failUnlessEqual(ic._debug_counts["inbound_announcement"], 1)
+            self.failUnlessEqual(ic._debug_counts["new_announcement"], 1)
+            self.failUnlessEqual(ic._debug_counts["update"], 0)
+            self.failUnlessEqual(ic._debug_counts["duplicate_announcement"], 0)
+            # now send a duplicate announcement: this should not notify clients
+            ca.remote_announce([ann1])
+            return fireEventually()
+        d.addCallback(_then)
+        def _then2(ign):
+            self.failUnlessEqual(len(announcements), 1)
+            self.failUnlessEqual(ic._debug_counts["inbound_announcement"], 2)
+            self.failUnlessEqual(ic._debug_counts["new_announcement"], 1)
+            self.failUnlessEqual(ic._debug_counts["update"], 0)
+            self.failUnlessEqual(ic._debug_counts["duplicate_announcement"], 1)
+            # and a replacement announcement: same FURL, new other stuff.
+            # Clients should be notified.
+            ca.remote_announce([ann1b])
+            return fireEventually()
+        d.addCallback(_then2)
+        def _then3(ign):
+            self.failUnlessEqual(len(announcements), 2)
+            self.failUnlessEqual(ic._debug_counts["inbound_announcement"], 3)
+            self.failUnlessEqual(ic._debug_counts["new_announcement"], 1)
+            self.failUnlessEqual(ic._debug_counts["update"], 1)
+            self.failUnlessEqual(ic._debug_counts["duplicate_announcement"], 1)
+            # test that the other stuff changed
+            self.failUnlessEqual(announcements[-1]["nickname"], u"nick1")
+            self.failUnlessEqual(announcements[-1]["my-version"], "ver24")
+        d.addCallback(_then3)
+        return d
+
+    def test_duplicate_receive_v2(self):
+        ic1 = IntroducerClient(None,
+                               "introducer.furl", u"my_nickname",
+                               "ver23", "oldest_version", {})
+        # we use a second client just to create a different-looking
+        # announcement
+        ic2 = IntroducerClient(None,
+                               "introducer.furl", u"my_nickname",
+                               "ver24","oldest_version",{})
+        announcements = []
+        def _received(nodeid, ann_d):
+            announcements.append( (nodeid, ann_d) )
+        ic1.subscribe_to("storage", _received)
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:36106/gydnp"
+        furl1a = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:7777/gydnp"
+        furl2 = "pb://ttwwooyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:36106/ttwwoo"
+
+        privkey = ecdsa.SigningKey.generate()
+        pubkey = privkey.get_verifying_key()
+        pubkey_hex = pubkey.to_string().encode("hex")
+
+        # ann1: ic1, furl1
+        # ann1a: ic1, furl1a (same SturdyRef, different connection hints)
+        # ann1b: ic2, furl1
+        # ann2: ic2, furl2
+
+        self.ann1 = ic1.create_announcement(furl1, "storage", "RIStorage",
+                                            privkey)
+        self.ann1a =  ic1.create_announcement(furl1a, "storage", "RIStorage",
+                                              privkey)
+        self.ann1b = ic2.create_announcement(furl1, "storage", "RIStorage",
+                                             privkey)
+        self.ann2 = ic2.create_announcement(furl2, "storage", "RIStorage",
+                                            privkey)
+
+        ic1.remote_announce_v2([self.ann1]) # queues eventual-send
+        d = fireEventually()
+        def _then1(ign):
+            self.failUnlessEqual(len(announcements), 1)
+            nodeid,ann_d = announcements[0]
+            self.failUnlessEqual(nodeid.encode("hex"), pubkey_hex)
+            self.failUnlessEqual(ann_d["FURL"], furl1)
+            self.failUnlessEqual(ann_d["my-version"], "ver23")
+        d.addCallback(_then1)
+
+        # now send a duplicate announcement. This should not fire the
+        # subscriber
+        d.addCallback(lambda ign: ic1.remote_announce_v2([self.ann1]))
+        d.addCallback(fireEventually)
+        def _then2(ign):
+            self.failUnlessEqual(len(announcements), 1)
+        d.addCallback(_then2)
+
+        # and a replacement announcement: same FURL, new other stuff. The
+        # subscriber *should* be fired.
+        d.addCallback(lambda ign: ic1.remote_announce_v2([self.ann1b]))
+        d.addCallback(fireEventually)
+        def _then3(ign):
+            self.failUnlessEqual(len(announcements), 2)
+            nodeid,ann_d = announcements[-1]
+            self.failUnlessEqual(nodeid.encode("hex"), pubkey_hex)
+            self.failUnlessEqual(ann_d["FURL"], furl1)
+            self.failUnlessEqual(ann_d["my-version"], "ver24")
+        d.addCallback(_then3)
+
+        # and a replacement announcement with a different FURL (it uses
+        # different connection hints)
+        d.addCallback(lambda ign: ic1.remote_announce_v2([self.ann1a]))
+        d.addCallback(fireEventually)
+        def _then4(ign):
+            self.failUnlessEqual(len(announcements), 3)
+            nodeid,ann_d = announcements[-1]
+            self.failUnlessEqual(nodeid.encode("hex"), pubkey_hex)
+            self.failUnlessEqual(ann_d["FURL"], furl1a)
+            self.failUnlessEqual(ann_d["my-version"], "ver23")
+        d.addCallback(_then4)
+
+        # now add a new subscription, which should be called with the
+        # backlog. The introducer only records one announcement per index, so
+        # the backlog will only have the latest message.
+        announcements2 = []
+        def _received2(nodeid, ann_d):
+            announcements2.append( (nodeid, ann_d) )
+        d.addCallback(lambda ign: ic1.subscribe_to("storage", _received2))
+        d.addCallback(fireEventually)
+        def _then5(ign):
+            self.failUnlessEqual(len(announcements2), 1)
+            nodeid,ann_d = announcements2[-1]
+            self.failUnlessEqual(nodeid.encode("hex"), pubkey_hex)
+            self.failUnlessEqual(ann_d["FURL"], furl1a)
+            self.failUnlessEqual(ann_d["my-version"], "ver23")
+        d.addCallback(_then5)
+        return d
+
 class SystemTestMixin(ServiceMixin, pollmixin.PollMixin):
 
     def create_tub(self, portnum=0):
@@ -88,36 +235,37 @@ class SystemTestMixin(ServiceMixin, pollmixin.PollMixin):
             assert self.central_portnum == portnum
         tub.setLocation("localhost:%d" % self.central_portnum)
 
+V1 = "v1"; V2 = "v2"
 class SystemTest(SystemTestMixin, unittest.TestCase):
 
-    def test_system(self):
-        self.basedir = "introducer/SystemTest/system"
-        os.makedirs(self.basedir)
-        return self.do_system_test(IntroducerService)
-    test_system.timeout = 480 # occasionally takes longer than 350s on "draco"
-
-    def do_system_test(self, create_introducer):
+    def do_system_test(self, server_version):
         self.create_tub()
-        introducer = create_introducer()
+        if server_version == V1:
+            introducer = old.IntroducerService_v1()
+        else:
+            introducer = IntroducerService()
         introducer.setServiceParent(self.parent)
         iff = os.path.join(self.basedir, "introducer.furl")
         tub = self.central_tub
         ifurl = self.central_tub.registerReference(introducer, furlFile=iff)
         self.introducer_furl = ifurl
 
-        NUMCLIENTS = 5
-        # we have 5 clients who publish themselves, and an extra one does
-        # which not. When the connections are fully established, all six nodes
+        # we have 5 clients who publish themselves as storage servers, and a
+        # sixth which does which not. All 6 clients subscriber to hear about
+        # storage. When the connections are fully established, all six nodes
         # should have 5 connections each.
+        NUM_STORAGE = 5
+        NUM_CLIENTS = 6
 
         clients = []
         tubs = {}
         received_announcements = {}
-        NUM_SERVERS = NUMCLIENTS
         subscribing_clients = []
         publishing_clients = []
+        privkeys = {}
+        expected_announcements = [0 for c in range(NUM_CLIENTS)]
 
-        for i in range(NUMCLIENTS+1):
+        for i in range(NUM_CLIENTS):
             tub = Tub()
             #tub.setOption("logLocalFailures", True)
             #tub.setOption("logRemoteFailures", True)
@@ -128,62 +276,163 @@ class SystemTest(SystemTestMixin, unittest.TestCase):
             tub.setLocation("localhost:%d" % portnum)
 
             log.msg("creating client %d: %s" % (i, tub.getShortTubID()))
-            c = IntroducerClient(tub, self.introducer_furl, u"nickname-%d" % i,
-                                 "version", "oldest")
+            if i == 0:
+                c = old.IntroducerClient_v1(tub, self.introducer_furl,
+                                            u"nickname-%d" % i,
+                                            "version", "oldest")
+            else:
+                c = IntroducerClient(tub, self.introducer_furl,
+                                     u"nickname-%d" % i,
+                                     "version", "oldest",
+                                     {"component": "component-v1"})
             received_announcements[c] = {}
             def got(serverid, ann_d, announcements):
                 announcements[serverid] = ann_d
             c.subscribe_to("storage", got, received_announcements[c])
             subscribing_clients.append(c)
-
-            if i < NUMCLIENTS:
-                node_furl = tub.registerReference(Referenceable())
-                c.publish(node_furl, "storage", "ri_name")
+            expected_announcements[i] += 1 # all expect a 'storage' announcement
+
+            node_furl = tub.registerReference(Referenceable())
+            if i < NUM_STORAGE:
+                if i == 1:
+                    # sign the announcement
+                    privkey = privkeys[c] = ecdsa.SigningKey.generate()
+                    c.publish(node_furl, "storage", "ri_name", privkey)
+                else:
+                    c.publish(node_furl, "storage", "ri_name")
                 publishing_clients.append(c)
-            # the last one does not publish anything
+            else:
+                # the last one does not publish anything
+                pass
+
+            if i == 0:
+                # users of the V1 client were required to publish a
+                # 'stub_client' record (somewhat after they published the
+                # 'storage' record), so the introducer could see their
+                # version. Match that behavior.
+                c.publish(node_furl, "stub_client", "stub_ri_name")
+
+            if i == 2:
+                # also publish something that nobody cares about
+                boring_furl = tub.registerReference(Referenceable())
+                c.publish(boring_furl, "boring", "ri_name")
 
             c.setServiceParent(self.parent)
             clients.append(c)
             tubs[c] = tub
 
-        def _wait_for_all_connections():
-            for c in subscribing_clients:
-                if len(received_announcements[c]) < NUM_SERVERS:
+
+        def _wait_for_connected(ign):
+            def _connected():
+                for c in clients:
+                    if not c.connected_to_introducer():
+                        return False
+                return True
+            return self.poll(_connected)
+
+        # we watch the clients to determine when the system has settled down.
+        # Then we can look inside the server to assert things about its
+        # state.
+
+        def _wait_for_expected_announcements(ign):
+            def _got_expected_announcements():
+                for i,c in enumerate(subscribing_clients):
+                    if len(received_announcements[c]) < expected_announcements[i]:
+                        return False
+                return True
+            return self.poll(_got_expected_announcements)
+
+        # before shutting down any Tub, we'd like to know that there are no
+        # messages outstanding
+
+        def _wait_until_idle(ign):
+            def _idle():
+                for c in subscribing_clients + publishing_clients:
+                    if c._debug_outstanding:
+                        return False
+                if introducer._debug_outstanding:
                     return False
-            return True
-        d = self.poll(_wait_for_all_connections)
+                return True
+            return self.poll(_idle)
+
+        d = defer.succeed(None)
+        d.addCallback(_wait_for_connected)
+        d.addCallback(_wait_for_expected_announcements)
+        d.addCallback(_wait_until_idle)
 
         def _check1(res):
             log.msg("doing _check1")
             dc = introducer._debug_counts
-            self.failUnlessEqual(dc["inbound_message"], NUM_SERVERS)
-            self.failUnlessEqual(dc["inbound_duplicate"], 0)
+            if server_version == V1:
+                # each storage server publishes a record, and (after its
+                # 'subscribe' has been ACKed) also publishes a "stub_client".
+                # The non-storage client (which subscribes) also publishes a
+                # stub_client. There is also one "boring" service. The number
+                # of messages is higher, because the stub_clients aren't
+                # published until after we get the 'subscribe' ack (since we
+                # don't realize that we're dealing with a v1 server [which
+                # needs stub_clients] until then), and the act of publishing
+                # the stub_client causes us to re-send all previous
+                # announcements.
+                self.failUnlessEqual(dc["inbound_message"] - dc["inbound_duplicate"],
+                                     NUM_STORAGE + NUM_CLIENTS + 1)
+            else:
+                # each storage server publishes a record. There is also one
+                # "stub_client" and one "boring"
+                self.failUnlessEqual(dc["inbound_message"], NUM_STORAGE+2)
+                self.failUnlessEqual(dc["inbound_duplicate"], 0)
             self.failUnlessEqual(dc["inbound_update"], 0)
-            self.failUnless(dc["outbound_message"])
+            self.failUnlessEqual(dc["inbound_subscribe"], NUM_CLIENTS)
+            # the number of outbound messages is tricky.. I think it depends
+            # upon a race between the publish and the subscribe messages.
+            self.failUnless(dc["outbound_message"] > 0)
+            # each client subscribes to "storage", and each server publishes
+            self.failUnlessEqual(dc["outbound_announcements"],
+                                 NUM_STORAGE*NUM_CLIENTS)
 
-            for c in clients:
-                self.failUnless(c.connected_to_introducer())
             for c in subscribing_clients:
                 cdc = c._debug_counts
                 self.failUnless(cdc["inbound_message"])
                 self.failUnlessEqual(cdc["inbound_announcement"],
-                                     NUM_SERVERS)
+                                     NUM_STORAGE)
                 self.failUnlessEqual(cdc["wrong_service"], 0)
                 self.failUnlessEqual(cdc["duplicate_announcement"], 0)
                 self.failUnlessEqual(cdc["update"], 0)
                 self.failUnlessEqual(cdc["new_announcement"],
-                                     NUM_SERVERS)
+                                     NUM_STORAGE)
                 anns = received_announcements[c]
-                self.failUnlessEqual(len(anns), NUM_SERVERS)
+                self.failUnlessEqual(len(anns), NUM_STORAGE)
 
                 nodeid0 = b32decode(tubs[clients[0]].tubID.upper())
                 ann_d = anns[nodeid0]
                 nick = ann_d["nickname"]
                 self.failUnlessEqual(type(nick), unicode)
                 self.failUnlessEqual(nick, u"nickname-0")
-            for c in publishing_clients:
-                cdc = c._debug_counts
-                self.failUnlessEqual(cdc["outbound_message"], 1)
+            if server_version == V1:
+                for c in publishing_clients:
+                    cdc = c._debug_counts
+                    expected = 1 # storage
+                    if c is clients[2]:
+                        expected += 1 # boring
+                    if c is not clients[0]:
+                        # the v2 client tries to call publish_v2, which fails
+                        # because the server is v1. It then re-sends
+                        # everything it has so far, plus a stub_client record
+                        expected = 2*expected + 1
+                    if c is clients[0]:
+                        # we always tell v1 client to send stub_client
+                        expected += 1
+                    self.failUnlessEqual(cdc["outbound_message"], expected)
+            else:
+                for c in publishing_clients:
+                    cdc = c._debug_counts
+                    expected = 1
+                    if c in [clients[0], # stub_client
+                             clients[2], # boring
+                             ]:
+                        expected = 2
+                    self.failUnlessEqual(cdc["outbound_message"], expected)
+            log.msg("_check1 done")
         d.addCallback(_check1)
 
         # force an introducer reconnect, by shutting down the Tub it's using
@@ -196,67 +445,52 @@ class SystemTest(SystemTestMixin, unittest.TestCase):
         d.addCallback(lambda _ign: log.msg("shutting down introducer's Tub"))
         d.addCallback(lambda _ign: self.central_tub.disownServiceParent())
 
-        def _wait_for_introducer_loss():
-            for c in clients:
-                if c.connected_to_introducer():
-                    return False
-            return True
-        d.addCallback(lambda res: self.poll(_wait_for_introducer_loss))
+        def _wait_for_introducer_loss(ign):
+            def _introducer_lost():
+                for c in clients:
+                    if c.connected_to_introducer():
+                        return False
+                return True
+            return self.poll(_introducer_lost)
+        d.addCallback(_wait_for_introducer_loss)
 
         def _restart_introducer_tub(_ign):
             log.msg("restarting introducer's Tub")
-
-            dc = introducer._debug_counts
-            self.expected_count = dc["inbound_message"] + NUM_SERVERS
-            self.expected_subscribe_count = dc["inbound_subscribe"] + NUMCLIENTS+1
-            introducer._debug0 = dc["outbound_message"]
-            for c in subscribing_clients:
-                cdc = c._debug_counts
-                c._debug0 = cdc["inbound_message"]
-
+            # reset counters
+            for i in range(NUM_CLIENTS):
+                c = subscribing_clients[i]
+                for k in c._debug_counts:
+                    c._debug_counts[k] = 0
+            for k in introducer._debug_counts:
+                introducer._debug_counts[k] = 0
+            expected_announcements[i] += 1 # new 'storage' for everyone
             self.create_tub(self.central_portnum)
             newfurl = self.central_tub.registerReference(introducer,
                                                          furlFile=iff)
             assert newfurl == self.introducer_furl
         d.addCallback(_restart_introducer_tub)
 
-        def _wait_for_introducer_reconnect():
-            # wait until:
-            #  all clients are connected
-            #  the introducer has received publish messages from all of them
-            #  the introducer has received subscribe messages from all of them
-            #  the introducer has sent (duplicate) announcements to all of them
-            #  all clients have received (duplicate) announcements
-            dc = introducer._debug_counts
-            for c in clients:
-                if not c.connected_to_introducer():
-                    return False
-            if dc["inbound_message"] < self.expected_count:
-                return False
-            if dc["inbound_subscribe"] < self.expected_subscribe_count:
-                return False
-            for c in subscribing_clients:
-                cdc = c._debug_counts
-                if cdc["inbound_message"] < c._debug0+1:
-                    return False
-            return True
-        d.addCallback(lambda res: self.poll(_wait_for_introducer_reconnect))
+        d.addCallback(_wait_for_connected)
+        d.addCallback(_wait_for_expected_announcements)
+        d.addCallback(_wait_until_idle)
+        d.addCallback(lambda _ign: log.msg(" reconnected"))
 
         def _check2(res):
             log.msg("doing _check2")
             # assert that the introducer sent out new messages, one per
             # subscriber
             dc = introducer._debug_counts
-            self.failUnlessEqual(dc["inbound_message"], 2*NUM_SERVERS)
-            self.failUnlessEqual(dc["inbound_duplicate"], NUM_SERVERS)
-            self.failUnlessEqual(dc["inbound_update"], 0)
-            self.failUnlessEqual(dc["outbound_message"],
-                                 introducer._debug0 + len(subscribing_clients))
-            for c in clients:
-                self.failUnless(c.connected_to_introducer())
+            self.failUnlessEqual(dc["outbound_announcements"],
+                                 NUM_STORAGE*NUM_CLIENTS)
+            self.failUnless(dc["outbound_message"] > 0)
+            self.failUnlessEqual(dc["inbound_subscribe"], NUM_CLIENTS)
             for c in subscribing_clients:
                 cdc = c._debug_counts
-                self.failUnlessEqual(cdc["duplicate_announcement"], NUM_SERVERS)
+                self.failUnlessEqual(cdc["inbound_message"], 1)
+                self.failUnlessEqual(cdc["inbound_announcement"], NUM_STORAGE)
+                self.failUnlessEqual(cdc["new_announcement"], 0)
+                self.failUnlessEqual(cdc["wrong_service"], 0)
+                self.failUnlessEqual(cdc["duplicate_announcement"], NUM_STORAGE)
         d.addCallback(_check2)
 
         # Then force an introducer restart, by shutting down the Tub,
@@ -267,71 +501,216 @@ class SystemTest(SystemTestMixin, unittest.TestCase):
 
         d.addCallback(lambda _ign: log.msg("shutting down introducer"))
         d.addCallback(lambda _ign: self.central_tub.disownServiceParent())
-        d.addCallback(lambda res: self.poll(_wait_for_introducer_loss))
+        d.addCallback(_wait_for_introducer_loss)
+        d.addCallback(lambda _ign: log.msg("introducer lost"))
 
         def _restart_introducer(_ign):
             log.msg("restarting introducer")
             self.create_tub(self.central_portnum)
-
-            for c in subscribing_clients:
-                # record some counters for later comparison. Stash the values
-                # on the client itself, because I'm lazy.
-                cdc = c._debug_counts
-                c._debug1 = cdc["inbound_announcement"]
-                c._debug2 = cdc["inbound_message"]
-                c._debug3 = cdc["new_announcement"]
-            newintroducer = create_introducer()
-            self.expected_message_count = NUM_SERVERS
-            self.expected_announcement_count = NUM_SERVERS*len(subscribing_clients)
-            self.expected_subscribe_count = len(subscribing_clients)
-            newfurl = self.central_tub.registerReference(newintroducer,
+            # reset counters
+            for i in range(NUM_CLIENTS):
+                c = subscribing_clients[i]
+                for k in c._debug_counts:
+                    c._debug_counts[k] = 0
+            expected_announcements[i] += 1 # new 'storage' for everyone
+            if server_version == V1:
+                introducer = old.IntroducerService_v1()
+            else:
+                introducer = IntroducerService()
+            newfurl = self.central_tub.registerReference(introducer,
                                                          furlFile=iff)
             assert newfurl == self.introducer_furl
         d.addCallback(_restart_introducer)
-        def _wait_for_introducer_reconnect2():
-            # wait until:
-            #  all clients are connected
-            #  the introducer has received publish messages from all of them
-            #  the introducer has received subscribe messages from all of them
-            #  the introducer has sent announcements for everybody to everybody
-            #  all clients have received all the (duplicate) announcements
-            # at that point, the system should be quiescent
-            dc = introducer._debug_counts
-            for c in clients:
-                if not c.connected_to_introducer():
-                    return False
-            if dc["inbound_message"] < self.expected_message_count:
-                return False
-            if dc["outbound_announcements"] < self.expected_announcement_count:
-                return False
-            if dc["inbound_subscribe"] < self.expected_subscribe_count:
-                return False
-            for c in subscribing_clients:
-                cdc = c._debug_counts
-                if cdc["inbound_announcement"] < c._debug1+NUM_SERVERS:
-                    return False
-            return True
-        d.addCallback(lambda res: self.poll(_wait_for_introducer_reconnect2))
+
+        d.addCallback(_wait_for_connected)
+        d.addCallback(_wait_for_expected_announcements)
+        d.addCallback(_wait_until_idle)
 
         def _check3(res):
             log.msg("doing _check3")
-            for c in clients:
-                self.failUnless(c.connected_to_introducer())
+            dc = introducer._debug_counts
+            self.failUnlessEqual(dc["outbound_announcements"],
+                                 NUM_STORAGE*NUM_CLIENTS)
+            self.failUnless(dc["outbound_message"] > 0)
+            self.failUnlessEqual(dc["inbound_subscribe"], NUM_CLIENTS)
             for c in subscribing_clients:
                 cdc = c._debug_counts
-                self.failUnless(cdc["inbound_announcement"] > c._debug1)
-                self.failUnless(cdc["inbound_message"] > c._debug2)
-                # there should have been no new announcements
-                self.failUnlessEqual(cdc["new_announcement"], c._debug3)
-                # and the right number of duplicate ones. There were
-                # NUM_SERVERS from the servertub restart, and there should be
-                # another NUM_SERVERS now
-                self.failUnlessEqual(cdc["duplicate_announcement"],
-                                     2*NUM_SERVERS)
+                self.failUnless(cdc["inbound_message"] > 0)
+                self.failUnlessEqual(cdc["inbound_announcement"], NUM_STORAGE)
+                self.failUnlessEqual(cdc["new_announcement"], 0)
+                self.failUnlessEqual(cdc["wrong_service"], 0)
+                self.failUnlessEqual(cdc["duplicate_announcement"], NUM_STORAGE)
 
         d.addCallback(_check3)
         return d
 
+
+    def test_system_v2_server(self):
+        self.basedir = "introducer/SystemTest/system_v2_server"
+        os.makedirs(self.basedir)
+        return self.do_system_test(V2)
+    test_system_v2_server.timeout = 480
+    # occasionally takes longer than 350s on "draco"
+
+    def test_system_v1_server(self):
+        self.basedir = "introducer/SystemTest/system_v1_server"
+        os.makedirs(self.basedir)
+        return self.do_system_test(V1)
+    test_system_v1_server.timeout = 480
+    # occasionally takes longer than 350s on "draco"
+
+from allmydata.util import base32
+class FakeRemoteReference:
+    def notifyOnDisconnect(self, *args, **kwargs): pass
+    def getRemoteTubID(self): return "62ubehyunnyhzs7r6vdonnm2hpi52w6y"
+
+class ClientInfo(unittest.TestCase):
+    def test_client_v2(self):
+        introducer = IntroducerService()
+        tub = introducer_furl = None
+        app_versions = {"whizzy": "fizzy"}
+        client_v2 = IntroducerClient(tub, introducer_furl, u"nick-v2",
+                                     "my_version", "oldest", app_versions)
+        #furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:0/swissnum"
+        #ann_s = client_v2.create_announcement(furl1, "storage", "RIStorage")
+        #introducer.remote_publish_v2(ann_s, Referenceable())
+        subscriber = FakeRemoteReference()
+        introducer.remote_subscribe_v2(subscriber, "storage",
+                                       client_v2._my_subscriber_info)
+        s = introducer.get_subscribers()
+        self.failUnlessEqual(len(s), 1)
+        sn, when, si, rref = s[0]
+        self.failUnlessIdentical(rref, subscriber)
+        self.failUnlessEqual(sn, "storage")
+        self.failUnlessEqual(si["version"], 0)
+        self.failUnlessEqual(si["oldest-supported"], "oldest")
+        self.failUnlessEqual(si["app-versions"], app_versions)
+        self.failUnlessEqual(si["nickname"], u"nick-v2")
+        self.failUnlessEqual(si["my-version"], "my_version")
+
+    def test_client_v1(self):
+        introducer = IntroducerService()
+        tub = introducer_furl = None
+        client_v1 = old.IntroducerClient_v1(tub, introducer_furl, u"nick-v1",
+                                            "my_version", "oldest")
+        subscriber = FakeRemoteReference()
+        introducer.remote_subscribe(subscriber, "storage")
+        # the v1 subscribe interface had no subscriber_info: that was usually
+        # sent in a separate stub_client pseudo-announcement
+        s = introducer.get_subscribers()
+        self.failUnlessEqual(len(s), 1)
+        sn, when, si, rref = s[0]
+        # rref will be a SubscriberAdapter_v1 around the real subscriber
+        self.failUnlessIdentical(rref.original, subscriber)
+        self.failUnlessEqual(si, None) # not known yet
+        self.failUnlessEqual(sn, "storage")
+
+        # now submit the stub_client announcement
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:0/swissnum"
+        ann = (furl1, "stub_client", "RIStubClient",
+               u"nick-v1".encode("utf-8"), "my_version", "oldest")
+        introducer.remote_publish(ann)
+        # the server should correlate the two
+        s = introducer.get_subscribers()
+        self.failUnlessEqual(len(s), 1)
+        sn, when, si, rref = s[0]
+        self.failUnlessIdentical(rref.original, subscriber)
+        self.failUnlessEqual(sn, "storage")
+
+        self.failUnlessEqual(si["version"], 0)
+        self.failUnlessEqual(si["oldest-supported"], "oldest")
+        # v1 announcements do not contain app-versions
+        self.failUnlessEqual(si["app-versions"], {})
+        self.failUnlessEqual(si["nickname"], u"nick-v1")
+        self.failUnlessEqual(si["my-version"], "my_version")
+
+        # a subscription that arrives after the stub_client announcement
+        # should be correlated too
+        subscriber2 = FakeRemoteReference()
+        introducer.remote_subscribe(subscriber2, "thing2")
+
+        s = introducer.get_subscribers()
+        subs = dict([(sn, (si,rref)) for sn, when, si, rref in s])
+        self.failUnlessEqual(len(subs), 2)
+        (si,rref) = subs["thing2"]
+        self.failUnlessIdentical(rref.original, subscriber2)
+        self.failUnlessEqual(si["version"], 0)
+        self.failUnlessEqual(si["oldest-supported"], "oldest")
+        # v1 announcements do not contain app-versions
+        self.failUnlessEqual(si["app-versions"], {})
+        self.failUnlessEqual(si["nickname"], u"nick-v1")
+        self.failUnlessEqual(si["my-version"], "my_version")
+
+class Announcements(unittest.TestCase):
+    def test_client_v2_unsigned(self):
+        introducer = IntroducerService()
+        tub = introducer_furl = None
+        app_versions = {"whizzy": "fizzy"}
+        client_v2 = IntroducerClient(tub, introducer_furl, u"nick-v2",
+                                     "my_version", "oldest", app_versions)
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:0/swissnum"
+        serverid = base32.a2b("62ubehyunnyhzs7r6vdonnm2hpi52w6y")
+        ann_s0 = client_v2.create_announcement(furl1, "storage", "RIStorage")
+        canary0 = Referenceable()
+        introducer.remote_publish_v2(ann_s0, canary0)
+        a = introducer.get_announcements()
+        self.failUnlessEqual(len(a), 1)
+        (index, (ann_s, canary, ann_d, when)) = a.items()[0]
+        self.failUnlessIdentical(canary, canary0)
+        self.failUnlessEqual(index, ("storage", serverid))
+        self.failUnlessEqual(ann_d["app-versions"], app_versions)
+        self.failUnlessEqual(ann_d["nickname"], u"nick-v2")
+        self.failUnlessEqual(ann_d["service-name"], "storage")
+        self.failUnlessEqual(ann_d["my-version"], "my_version")
+        self.failUnlessEqual(ann_d["FURL"], furl1)
+
+    def test_client_v2_signed(self):
+        introducer = IntroducerService()
+        tub = introducer_furl = None
+        app_versions = {"whizzy": "fizzy"}
+        client_v2 = IntroducerClient(tub, introducer_furl, u"nick-v2",
+                                     "my_version", "oldest", app_versions)
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:0/swissnum"
+        serverid = base32.a2b("62ubehyunnyhzs7r6vdonnm2hpi52w6y")
+        sk = ecdsa.SigningKey.generate()
+        pk = sk.get_verifying_key()
+        pks = pk.to_string()
+        ann_s0 = client_v2.create_announcement(furl1, "storage", "RIStorage", sk)
+        canary0 = Referenceable()
+        introducer.remote_publish_v2(ann_s0, canary0)
+        a = introducer.get_announcements()
+        self.failUnlessEqual(len(a), 1)
+        (index, (ann_s, canary, ann_d, when)) = a.items()[0]
+        self.failUnlessIdentical(canary, canary0)
+        self.failUnlessEqual(index, ("storage", pks)) # index is pubkey string
+        self.failUnlessEqual(ann_d["app-versions"], app_versions)
+        self.failUnlessEqual(ann_d["nickname"], u"nick-v2")
+        self.failUnlessEqual(ann_d["service-name"], "storage")
+        self.failUnlessEqual(ann_d["my-version"], "my_version")
+        self.failUnlessEqual(ann_d["FURL"], furl1)
+
+    def test_client_v1(self):
+        introducer = IntroducerService()
+        tub = introducer_furl = None
+
+        furl1 = "pb://62ubehyunnyhzs7r6vdonnm2hpi52w6y@127.0.0.1:0/swissnum"
+        serverid = base32.a2b("62ubehyunnyhzs7r6vdonnm2hpi52w6y")
+        ann = (furl1, "storage", "RIStorage",
+               u"nick-v1".encode("utf-8"), "my_version", "oldest")
+        introducer.remote_publish(ann)
+
+        a = introducer.get_announcements()
+        self.failUnlessEqual(len(a), 1)
+        (index, (ann_s, canary, ann_d, when)) = a.items()[0]
+        self.failUnlessEqual(canary, None)
+        self.failUnlessEqual(index, ("storage", serverid))
+        self.failUnlessEqual(ann_d["app-versions"], {})
+        self.failUnlessEqual(ann_d["nickname"], u"nick-v1".encode("utf-8"))
+        self.failUnlessEqual(ann_d["service-name"], "storage")
+        self.failUnlessEqual(ann_d["my-version"], "my_version")
+        self.failUnlessEqual(ann_d["FURL"], furl1)
+
+
 class TooNewServer(IntroducerService):
     VERSION = { "http://allmydata.org/tahoe/protocols/introducer/v999":
                  { },
@@ -359,7 +738,7 @@ class NonV1Server(SystemTestMixin, unittest.TestCase):
         tub.setLocation("localhost:%d" % portnum)
 
         c = IntroducerClient(tub, self.introducer_furl,
-                             u"nickname-client", "version", "oldest")
+                             u"nickname-client", "version", "oldest", {})
         announcements = {}
         def got(serverid, ann_d):
             announcements[serverid] = ann_d
@@ -388,3 +767,13 @@ class DecodeFurl(unittest.TestCase):
         nodeid = b32decode(m.group(1).upper())
         self.failUnlessEqual(nodeid, "\x9fM\xf2\x19\xcckU0\xbf\x03\r\x10\x99\xfb&\x9b-\xc7A\x1d")
 
+
+# add tests of StorageFarmBroker: if it receives duplicate announcements, it
+# should leave the Reconnector in place, also if it receives
+# same-FURL-different-misc, but if it receives same-nodeid-different-FURL, it
+# should tear down the Reconnector and make a new one. This behavior used to
+# live in the IntroducerClient, and thus used to be tested by test_introducer
+
+# copying more tests from old branch:
+
+#  then also add Upgrade test
diff --git a/src/allmydata/test/test_system.py b/src/allmydata/test/test_system.py
index bf6af09..b7b3c22 100644
--- a/src/allmydata/test/test_system.py
+++ b/src/allmydata/test/test_system.py
@@ -778,7 +778,7 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
                 newappverstr = "%s: %s" % (allmydata.__appname__, altverstr)
 
                 self.failUnless((appverstr in res) or (newappverstr in res), (appverstr, newappverstr, res))
-                self.failUnless("Announcement Summary: storage: 5, stub_client: 5" in res)
+                self.failUnless("Announcement Summary: storage: 5" in res)
                 self.failUnless("Subscription Summary: storage: 5" in res)
             except unittest.FailTest:
                 print
@@ -795,9 +795,9 @@ class SystemTest(SystemTestMixin, RunBinTahoeMixin, unittest.TestCase):
                 self.failUnlessEqual(data["subscription_summary"],
                                      {"storage": 5})
                 self.failUnlessEqual(data["announcement_summary"],
-                                     {"storage": 5, "stub_client": 5})
+                                     {"storage": 5})
                 self.failUnlessEqual(data["announcement_distinct_hosts"],
-                                     {"storage": 1, "stub_client": 1})
+                                     {"storage": 1})
             except unittest.FailTest:
                 print
                 print "GET %s?t=json output was:" % self.introweb_url
diff --git a/src/allmydata/web/introweb.py b/src/allmydata/web/introweb.py
index 28273bd..be950c4 100644
--- a/src/allmydata/web/introweb.py
+++ b/src/allmydata/web/introweb.py
@@ -29,15 +29,20 @@ class IntroducerRoot(rend.Page):
 
     def render_JSON(self, ctx):
         res = {}
-        clients = self.introducer_service.get_subscribers()
-        subscription_summary = dict([ (name, len(clients[name]))
-                                      for name in clients ])
-        res["subscription_summary"] = subscription_summary
+
+        counts = {}
+        subscribers = self.introducer_service.get_subscribers()
+        for (service_name, ign, ign, ign) in subscribers:
+            if service_name not in counts:
+                counts[service_name] = 0
+            counts[service_name] += 1
+        res["subscription_summary"] = counts
 
         announcement_summary = {}
         service_hosts = {}
-        for (ann,when) in self.introducer_service.get_announcements().values():
-            (furl, service_name, ri_name, nickname, ver, oldest) = ann
+        for a in self.introducer_service.get_announcements().values():
+            (_, _, ann_d, when) = a
+            service_name = ann_d["service-name"]
             if service_name not in announcement_summary:
                 announcement_summary[service_name] = 0
             announcement_summary[service_name] += 1
@@ -50,6 +55,7 @@ class IntroducerRoot(rend.Page):
             # enough: when multiple services are run on a single host,
             # they're usually either configured with the same addresses,
             # or setLocationAutomatically picks up the same interfaces.
+            furl = ann_d["FURL"]
             locations = SturdyRef(furl).getTubRef().getLocations()
             # list of tuples, ("ipv4", host, port)
             host = frozenset([hint[1]
@@ -74,8 +80,9 @@ class IntroducerRoot(rend.Page):
 
     def render_announcement_summary(self, ctx, data):
         services = {}
-        for (ann,when) in self.introducer_service.get_announcements().values():
-            (furl, service_name, ri_name, nickname, ver, oldest) = ann
+        for a in self.introducer_service.get_announcements().values():
+            (_, _, ann_d, when) = a
+            service_name = ann_d["service-name"]
             if service_name not in services:
                 services[service_name] = 0
             services[service_name] += 1
@@ -85,64 +92,51 @@ class IntroducerRoot(rend.Page):
                           for service_name in service_names])
 
     def render_client_summary(self, ctx, data):
+        counts = {}
         clients = self.introducer_service.get_subscribers()
-        service_names = clients.keys()
-        service_names.sort()
-        return ", ".join(["%s: %d" % (service_name, len(clients[service_name]))
-                          for service_name in service_names])
+        for (service_name, ign, ign, ign) in clients:
+            if service_name not in counts:
+                counts[service_name] = 0
+            counts[service_name] += 1
+        return ", ".join([ "%s: %d" % (name, counts[name])
+                           for name in sorted(counts.keys()) ] )
 
     def data_services(self, ctx, data):
         introsvc = self.introducer_service
-        ann = [(since,a)
-               for (a,since) in introsvc.get_announcements().values()
-               if a[1] != "stub_client"]
-        ann.sort(lambda a,b: cmp( (a[1][1], a), (b[1][1], b) ) )
+        ann = []
+        for a in introsvc.get_announcements().values():
+            (_, _, ann_d, when) = a
+            if ann_d["service-name"] == "stub_client":
+                continue
+            ann.append( (when, ann_d) )
+        ann.sort(key=lambda x: (x[1]["service-name"], x[1]["nickname"]))
+        # this used to be:
+        #ann.sort(lambda a,b: cmp( (a[1][1], a), (b[1][1], b) ) )
+        # service_name was the primary key, then the whole tuple (starting
+        # with the furl) was the secondary key
         return ann
 
-    def render_service_row(self, ctx, (since,announcement)):
-        (furl, service_name, ri_name, nickname, ver, oldest) = announcement
-        sr = SturdyRef(furl)
+    def render_service_row(self, ctx, (since,ann_d)):
+        sr = SturdyRef(ann_d["FURL"])
         nodeid = sr.tubID
         advertised = self.show_location_hints(sr)
-        ctx.fillSlots("peerid", "%s %s" % (nodeid, nickname))
+        ctx.fillSlots("peerid", "%s %s" % (nodeid, ann_d["nickname"]))
         ctx.fillSlots("advertised", " ".join(advertised))
         ctx.fillSlots("connected", "?")
         TIME_FORMAT = "%H:%M:%S %d-%b-%Y"
         ctx.fillSlots("announced",
                       time.strftime(TIME_FORMAT, time.localtime(since)))
-        ctx.fillSlots("version", ver)
-        ctx.fillSlots("service_name", service_name)
+        ctx.fillSlots("version", ann_d["my-version"])
+        ctx.fillSlots("service_name", ann_d["service-name"])
         return ctx.tag
 
     def data_subscribers(self, ctx, data):
-        # use the "stub_client" announcements to get information per nodeid
-        clients = {}
-        for (ann,when) in self.introducer_service.get_announcements().values():
-            if ann[1] != "stub_client":
-                continue
-            (furl, service_name, ri_name, nickname, ver, oldest) = ann
-            sr = SturdyRef(furl)
-            nodeid = sr.tubID
-            clients[nodeid] = ann
-
-        # then we actually provide information per subscriber
-        s = []
-        introsvc = self.introducer_service
-        for service_name, subscribers in introsvc.get_subscribers().items():
-            for (rref, timestamp) in subscribers.items():
-                sr = rref.getSturdyRef()
-                nodeid = sr.tubID
-                ann = clients.get(nodeid)
-                s.append( (service_name, rref, timestamp, ann) )
-        s.sort()
-        return s
+        return self.introducer_service.get_subscribers()
 
     def render_subscriber_row(self, ctx, s):
-        (service_name, rref, since, ann) = s
-        nickname = "?"
-        version = "?"
-        if ann:
-            (furl, service_name_2, ri_name, nickname, version, oldest) = ann
+        (service_name, since, info, rref) = s
+        nickname = info.get("nickname", "?")
+        version = info.get("my-version", "?")
 
         sr = rref.getSturdyRef()
         # if the subscriber didn't do Tub.setLocation, nodeid will be None
