diff --git a/src/allmydata/blacklist.py b/src/allmydata/blacklist.py
index f0af41df4..aebede6af 100644
--- a/src/allmydata/blacklist.py
+++ b/src/allmydata/blacklist.py
@@ -1,7 +1,7 @@
 
 import os
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.python import log as twisted_log
 
@@ -56,8 +56,8 @@ class Blacklist:
         return reason
 
 
-class ProhibitedNode:
-    implements(IFileNode)
+@implementer(IFileNode)
+class ProhibitedNode(object):
 
     def __init__(self, wrapped_node, reason):
         assert IFilesystemNode.providedBy(wrapped_node), wrapped_node
diff --git a/src/allmydata/check_results.py b/src/allmydata/check_results.py
index 4071de6a0..df6887a4e 100644
--- a/src/allmydata/check_results.py
+++ b/src/allmydata/check_results.py
@@ -1,11 +1,11 @@
 
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata.interfaces import ICheckResults, ICheckAndRepairResults, \
      IDeepCheckResults, IDeepCheckAndRepairResults, IURI, IDisplayableServer
 from allmydata.util import base32
 
-class CheckResults:
-    implements(ICheckResults)
+@implementer(ICheckResults)
+class CheckResults(object):
 
     def __init__(self, uri, storage_index,
                  healthy, recoverable, count_happiness,
@@ -146,8 +146,8 @@ class CheckResults:
     def get_servermap(self):
         return self._servermap
 
-class CheckAndRepairResults:
-    implements(ICheckAndRepairResults)
+@implementer(ICheckAndRepairResults)
+class CheckAndRepairResults(object):
 
     def __init__(self, storage_index):
         self.storage_index = storage_index
@@ -206,8 +206,8 @@ class DeepResultsBase:
         return self.stats
 
 
+@implementer(IDeepCheckResults)
 class DeepCheckResults(DeepResultsBase):
-    implements(IDeepCheckResults)
 
     def add_check(self, r, path):
         if not r:
@@ -234,8 +234,8 @@ class DeepCheckResults(DeepResultsBase):
                 }
 
 
+@implementer(IDeepCheckAndRepairResults)
 class DeepCheckAndRepairResults(DeepResultsBase):
-    implements(IDeepCheckAndRepairResults)
 
     def __init__(self, root_storage_index):
         DeepResultsBase.__init__(self, root_storage_index)
diff --git a/src/allmydata/client.py b/src/allmydata/client.py
index 80332b408..0e7456bab 100644
--- a/src/allmydata/client.py
+++ b/src/allmydata/client.py
@@ -2,7 +2,7 @@ import os, stat, time, weakref
 from allmydata import node
 from base64 import urlsafe_b64encode
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import reactor, defer
 from twisted.application import service
 from twisted.application.internet import TimerService
@@ -153,8 +153,8 @@ class Terminator(service.Service):
         return service.Service.stopService(self)
 
 
+@implementer(IStatsProducer)
 class Client(node.Node, pollmixin.PollMixin):
-    implements(IStatsProducer)
 
     PORTNUMFILE = "client.port"
     STOREDIR = 'storage'
diff --git a/src/allmydata/codec.py b/src/allmydata/codec.py
index 25e600227..1ceb146e4 100644
--- a/src/allmydata/codec.py
+++ b/src/allmydata/codec.py
@@ -1,14 +1,14 @@
 # -*- test-case-name: allmydata.test.test_encode_share -*-
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from allmydata.util import mathutil
 from allmydata.util.assertutil import precondition
 from allmydata.interfaces import ICodecEncoder, ICodecDecoder
 import zfec
 
+@implementer(ICodecEncoder)
 class CRSEncoder(object):
-    implements(ICodecEncoder)
     ENCODER_TYPE = "crs"
 
     def set_params(self, data_size, required_shares, max_shares):
@@ -45,8 +45,8 @@ class CRSEncoder(object):
 
         return defer.succeed((shares, desired_share_ids))
 
+@implementer(ICodecDecoder)
 class CRSDecoder(object):
-    implements(ICodecDecoder)
 
     def set_params(self, data_size, required_shares, max_shares):
         self.data_size = data_size
diff --git a/src/allmydata/control.py b/src/allmydata/control.py
index 7bd8eedab..69ac9a62e 100644
--- a/src/allmydata/control.py
+++ b/src/allmydata/control.py
@@ -1,6 +1,6 @@
 
 import os, time, tempfile
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.application import service
 from twisted.internet import defer
 from twisted.internet.interfaces import IConsumer
@@ -37,8 +37,8 @@ def log_memory_usage(where=""):
                                               stats["VmPeak"],
                                               where))
 
+@implementer(IConsumer)
 class FileWritingConsumer:
-    implements(IConsumer)
     def __init__(self, filename):
         self.done = False
         self.f = open(filename, "wb")
@@ -54,8 +54,8 @@ class FileWritingConsumer:
         self.done = True
         self.f.close()
 
+@implementer(RIControlClient)
 class ControlServer(Referenceable, service.Service):
-    implements(RIControlClient)
 
     def remote_wait_for_client_connections(self, num_clients):
         return self.parent.debug_wait_for_client_connections(num_clients)
@@ -245,8 +245,8 @@ class SpeedTest:
             os.unlink(fn)
         return res
 
-class DiscardingConsumer:
-    implements(IConsumer)
+@implementer(IConsumer)
+class DiscardingConsumer(object):
     def __init__(self):
         self.done = False
     def registerProducer(self, p, streaming):
diff --git a/src/allmydata/dirnode.py b/src/allmydata/dirnode.py
index 620c7e398..f5f4e2073 100644
--- a/src/allmydata/dirnode.py
+++ b/src/allmydata/dirnode.py
@@ -1,7 +1,7 @@
 """Directory Node implementation."""
 import time, unicodedata
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from foolscap.api import fireEventually
 import simplejson
@@ -256,8 +256,8 @@ def _pack_normalized_children(children, writekey, deep_immutable=False):
         entries.append(netstring(entry))
     return "".join(entries)
 
-class DirectoryNode:
-    implements(IDirectoryNode, ICheckable, IDeepCheckable)
+@implementer(IDirectoryNode, ICheckable, IDeepCheckable)
+class DirectoryNode(object):
     filenode_class = MutableFileNode
 
     def __init__(self, filenode, nodemaker, uploader):
diff --git a/src/allmydata/frontends/auth.py b/src/allmydata/frontends/auth.py
index 712a888a0..2c72a020e 100644
--- a/src/allmydata/frontends/auth.py
+++ b/src/allmydata/frontends/auth.py
@@ -1,6 +1,6 @@
 import os
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.web.client import getPage
 from twisted.internet import defer
 from twisted.cred import error, checkers, credentials
@@ -21,8 +21,8 @@ class FTPAvatarID:
         self.username = username
         self.rootcap = rootcap
 
-class AccountFileChecker:
-    implements(checkers.ICredentialsChecker)
+@implementer(checkers.ICredentialsChecker)
+class AccountFileChecker(object):
     credentialInterfaces = (credentials.IUsernamePassword,
                             credentials.IUsernameHashedPassword,
                             credentials.ISSHPrivateKey)
@@ -108,8 +108,8 @@ class AccountFileChecker:
 
         return defer.fail(error.UnauthorizedLogin())
 
-class AccountURLChecker:
-    implements(checkers.ICredentialsChecker)
+@implementer(checkers.ICredentialsChecker)
+class AccountURLChecker(object):
     credentialInterfaces = (credentials.IUsernamePassword,)
 
     def __init__(self, client, auth_url):
diff --git a/src/allmydata/frontends/ftpd.py b/src/allmydata/frontends/ftpd.py
index 9791b813a..18f6ff423 100644
--- a/src/allmydata/frontends/ftpd.py
+++ b/src/allmydata/frontends/ftpd.py
@@ -1,7 +1,7 @@
 
 from types import NoneType
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.application import service, strports
 from twisted.internet import defer
 from twisted.internet.interfaces import IConsumer
@@ -15,16 +15,16 @@ from allmydata.immutable.upload import FileHandle
 from allmydata.util.fileutil import EncryptedTemporaryFile
 from allmydata.util.assertutil import precondition
 
-class ReadFile:
-    implements(ftp.IReadFile)
+@implementer(ftp.IReadFile)
+class ReadFile(object):
     def __init__(self, node):
         self.node = node
     def send(self, consumer):
         d = self.node.read(consumer)
         return d # when consumed
 
-class FileWriter:
-    implements(IConsumer)
+@implementer(IConsumer)
+class FileWriter(object):
 
     def registerProducer(self, producer, streaming):
         if not streaming:
@@ -41,8 +41,8 @@ class FileWriter:
     def write(self, data):
         self.f.write(data)
 
-class WriteFile:
-    implements(ftp.IWriteFile)
+@implementer(ftp.IWriteFile)
+class WriteFile(object):
 
     def __init__(self, parent, childname, convergence):
         self.parent = parent
@@ -73,8 +73,8 @@ class IntishPermissions(filepath.Permissions):
     def __and__(self, other):
         return self._tahoe_statModeInt & other
 
-class Handler:
-    implements(ftp.IFTPShell)
+@implementer(ftp.IFTPShell)
+class Handler(object):
     def __init__(self, client, rootnode, username, convergence):
         self.client = client
         self.root = rootnode
@@ -292,8 +292,8 @@ class Handler:
 from allmydata.frontends.auth import AccountURLChecker, AccountFileChecker, NeedRootcapLookupScheme
 
 
-class Dispatcher:
-    implements(portal.IRealm)
+@implementer(portal.IRealm)
+class Dispatcher(object):
     def __init__(self, client):
         self.client = client
 
diff --git a/src/allmydata/frontends/sftpd.py b/src/allmydata/frontends/sftpd.py
index f4a39cb9b..028ea7ee5 100644
--- a/src/allmydata/frontends/sftpd.py
+++ b/src/allmydata/frontends/sftpd.py
@@ -4,7 +4,7 @@ from types import NoneType
 from stat import S_IFREG, S_IFDIR
 from time import time, strftime, localtime
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.python import components
 from twisted.application import service, strports
 from twisted.conch.ssh import factory, keys, session
@@ -294,8 +294,8 @@ def _direntry_for(filenode_or_parent, childname, filenode=None):
     return None
 
 
+@implementer(IConsumer)
 class OverwriteableFileConsumer(PrefixingLogMixin):
-    implements(IConsumer)
     """I act both as a consumer for the download of the original file contents, and as a
     wrapper for a temporary file that records the downloaded data and any overwrites.
     I use a priority queue to keep track of which regions of the file have been overwritten
@@ -566,8 +566,8 @@ class OverwriteableFileConsumer(PrefixingLogMixin):
 SIZE_THRESHOLD = 1000
 
 
+@implementer(ISFTPFile)
 class ShortReadOnlySFTPFile(PrefixingLogMixin):
-    implements(ISFTPFile)
     """I represent a file handle to a particular file on an SFTP connection.
     I am used only for short immutable files opened in read-only mode.
     When I am created, the file contents start to be downloaded to memory.
@@ -644,8 +644,8 @@ class ShortReadOnlySFTPFile(PrefixingLogMixin):
         return defer.execute(_denied)
 
 
+@implementer(ISFTPFile)
 class GeneralSFTPFile(PrefixingLogMixin):
-    implements(ISFTPFile)
     """I represent a file handle to a particular file on an SFTP connection.
     I wrap an instance of OverwriteableFileConsumer, which is responsible for
     storing the file contents. In order to allow write requests to be satisfied
@@ -993,8 +993,8 @@ def _reload():
     global all_heisenfiles
     all_heisenfiles = {}
 
+@implementer(ISFTPServer)
 class SFTPUserHandler(ConchUser, PrefixingLogMixin):
-    implements(ISFTPServer)
     def __init__(self, client, rootnode, username):
         ConchUser.__init__(self)
         PrefixingLogMixin.__init__(self, facility="tahoe.sftp", prefix=username)
@@ -1894,8 +1894,8 @@ class SFTPUserHandler(ConchUser, PrefixingLogMixin):
         return d
 
 
-class FakeTransport:
-    implements(ITransport)
+@implementer(ITransport)
+class FakeTransport(object):
     def write(self, data):
         logmsg("FakeTransport.write(<data of length %r>)" % (len(data),), level=NOISY)
 
@@ -1908,8 +1908,8 @@ class FakeTransport:
     # getPeer and getHost can just raise errors, since we don't know what to return
 
 
+@implementer(ISession)
 class ShellSession(PrefixingLogMixin):
-    implements(ISession)
     def __init__(self, userHandler):
         PrefixingLogMixin.__init__(self, facility="tahoe.sftp")
         if noisy: self.log(".__init__(%r)" % (userHandler), level=NOISY)
@@ -1965,8 +1965,8 @@ components.registerAdapter(ShellSession, SFTPUserHandler, ISession)
 
 from allmydata.frontends.auth import AccountURLChecker, AccountFileChecker, NeedRootcapLookupScheme
 
-class Dispatcher:
-    implements(portal.IRealm)
+@implementer(portal.IRealm)
+class Dispatcher(object):
     def __init__(self, client):
         self._client = client
 
diff --git a/src/allmydata/immutable/checker.py b/src/allmydata/immutable/checker.py
index d931a15be..317d4af90 100644
--- a/src/allmydata/immutable/checker.py
+++ b/src/allmydata/immutable/checker.py
@@ -1,4 +1,4 @@
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from foolscap.api import DeadReferenceError, RemoteException
 from allmydata import hashtree, codec, uri
@@ -27,8 +27,8 @@ class BadOrMissingHash(IntegrityCheckReject):
 class UnsupportedErasureCodec(BadURIExtension):
     pass
 
-class ValidatedExtendedURIProxy:
-    implements(IValidatedThingProxy)
+@implementer(IValidatedThingProxy)
+class ValidatedExtendedURIProxy(object):
     """ I am a front-end for a remote UEB (using a local ReadBucketProxy),
     responsible for retrieving and validating the elements from the UEB."""
 
diff --git a/src/allmydata/immutable/downloader/segmentation.py b/src/allmydata/immutable/downloader/segmentation.py
index 07307c367..0acf09d9b 100644
--- a/src/allmydata/immutable/downloader/segmentation.py
+++ b/src/allmydata/immutable/downloader/segmentation.py
@@ -1,7 +1,7 @@
 
 import time
 now = time.time
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.internet.interfaces import IPushProducer
 from foolscap.api import eventually
@@ -11,14 +11,14 @@ from allmydata.interfaces import DownloadStopped
 
 from common import BadSegmentNumberError, WrongSegmentError
 
-class Segmentation:
+@implementer(IPushProducer)
+class Segmentation(object):
     """I am responsible for a single offset+size read of the file. I handle
     segmentation: I figure out which segments are necessary, request them
     (from my CiphertextDownloader) in order, and trim the segments down to
     match the offset+size span. I use the Producer/Consumer interface to only
     request one segment at a time.
     """
-    implements(IPushProducer)
     def __init__(self, node, offset, size, consumer, read_ev, logparent=None):
         self._node = node
         self._hungry = True
diff --git a/src/allmydata/immutable/downloader/status.py b/src/allmydata/immutable/downloader/status.py
index e9174b6bc..74e5fc7b6 100644
--- a/src/allmydata/immutable/downloader/status.py
+++ b/src/allmydata/immutable/downloader/status.py
@@ -1,6 +1,6 @@
 
 import itertools
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata.interfaces import IDownloadStatus
 
 class ReadEvent:
@@ -64,10 +64,10 @@ class BlockRequestEvent:
         self._ds.update_last_timestamp(when)
 
 
-class DownloadStatus:
+@implementer(IDownloadStatus)
+class DownloadStatus(object):
     # There is one DownloadStatus for each CiphertextFileNode. The status
     # object will keep track of all activity for that node.
-    implements(IDownloadStatus)
     statusid_counter = itertools.count(0)
 
     def __init__(self, storage_index, size):
diff --git a/src/allmydata/immutable/encode.py b/src/allmydata/immutable/encode.py
index 8cc32d35a..efc7ac3f6 100644
--- a/src/allmydata/immutable/encode.py
+++ b/src/allmydata/immutable/encode.py
@@ -1,7 +1,7 @@
 # -*- test-case-name: allmydata.test.test_encode -*-
 
 import time
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from foolscap.api import fireEventually
 from allmydata import uri
@@ -71,8 +71,8 @@ GiB=1024*MiB
 TiB=1024*GiB
 PiB=1024*TiB
 
+@implementer(IEncoder)
 class Encoder(object):
-    implements(IEncoder)
 
     def __init__(self, log_parent=None, upload_status=None, progress=None):
         object.__init__(self)
diff --git a/src/allmydata/immutable/filenode.py b/src/allmydata/immutable/filenode.py
index e00e69c98..ff15843a8 100644
--- a/src/allmydata/immutable/filenode.py
+++ b/src/allmydata/immutable/filenode.py
@@ -2,7 +2,7 @@
 import binascii
 from time import time as now
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 
 from allmydata import uri
@@ -182,12 +182,12 @@ class CiphertextFileNode:
                     monitor=monitor)
         return v.start()
 
-class DecryptingConsumer:
+@implementer(IConsumer, IDownloadStatusHandlingConsumer)
+class DecryptingConsumer(object):
     """I sit between a CiphertextDownloader (which acts as a Producer) and
     the real Consumer, decrypting everything that passes by. The real
     Consumer sees the real Producer, but the Producer sees us instead of the
     real consumer."""
-    implements(IConsumer, IDownloadStatusHandlingConsumer)
 
     def __init__(self, consumer, readkey, offset):
         self._consumer = consumer
@@ -227,8 +227,8 @@ class DecryptingConsumer:
             self._download_status.add_misc_event("AES", started, now())
         self._consumer.write(plaintext)
 
-class ImmutableFileNode:
-    implements(IImmutableFileNode)
+@implementer(IImmutableFileNode)
+class ImmutableFileNode(object):
 
     # I wrap a CiphertextFileNode with a decryption key
     def __init__(self, filecap, storage_broker, secret_holder, terminator,
diff --git a/src/allmydata/immutable/layout.py b/src/allmydata/immutable/layout.py
index 8d9a8f035..c634702ab 100644
--- a/src/allmydata/immutable/layout.py
+++ b/src/allmydata/immutable/layout.py
@@ -1,5 +1,5 @@
 import struct
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from allmydata.interfaces import IStorageBucketWriter, IStorageBucketReader, \
      FileTooLargeError, HASH_SIZE
@@ -94,8 +94,8 @@ def make_write_bucket_proxy(rref, server,
                                   num_share_hashes, uri_extension_size_max)
     return wbp
 
-class WriteBucketProxy:
-    implements(IStorageBucketWriter)
+@implementer(IStorageBucketWriter)
+class WriteBucketProxy(object):
     fieldsize = 4
     fieldstruct = ">L"
 
@@ -289,8 +289,8 @@ class WriteBucketProxy_v2(WriteBucketProxy):
         assert len(offset_data) == 0x44, len(offset_data)
         self._offset_data = offset_data
 
-class ReadBucketProxy:
-    implements(IStorageBucketReader)
+@implementer(IStorageBucketReader)
+class ReadBucketProxy(object):
 
     MAX_UEB_SIZE = 2000 # actual size is closer to 419, but varies by a few bytes
 
diff --git a/src/allmydata/immutable/literal.py b/src/allmydata/immutable/literal.py
index b18dccb6c..d00aedec0 100644
--- a/src/allmydata/immutable/literal.py
+++ b/src/allmydata/immutable/literal.py
@@ -1,13 +1,13 @@
 from cStringIO import StringIO
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.internet.interfaces import IPushProducer
 from twisted.protocols import basic
 from allmydata.interfaces import IImmutableFileNode, ICheckable
 from allmydata.uri import LiteralFileURI
 
+@implementer(IImmutableFileNode, ICheckable)
 class _ImmutableFileNodeBase(object):
-    implements(IImmutableFileNode, ICheckable)
 
     def get_write_uri(self):
         return None
@@ -44,8 +44,8 @@ class _ImmutableFileNodeBase(object):
             return True
 
 
-class LiteralProducer:
-    implements(IPushProducer)
+@implementer(IPushProducer)
+class LiteralProducer(object):
 
     def pauseProducing(self):
         pass
diff --git a/src/allmydata/immutable/offloaded.py b/src/allmydata/immutable/offloaded.py
index 937dceae8..5b9e5803b 100644
--- a/src/allmydata/immutable/offloaded.py
+++ b/src/allmydata/immutable/offloaded.py
@@ -1,6 +1,6 @@
 
 import os, stat, time, weakref
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from foolscap.api import Referenceable, DeadReferenceError, eventually
 import allmydata # for __full_version__
@@ -123,12 +123,12 @@ class CHKCheckerAndUEBFetcher:
         return False
 
 
+@implementer(interfaces.RICHKUploadHelper)
 class CHKUploadHelper(Referenceable, upload.CHKUploader):
     """I am the helper-server -side counterpart to AssistedUploader. I handle
     peer selection, encoding, and share pushing. I read ciphertext from the
     remote AssistedUploader.
     """
-    implements(interfaces.RICHKUploadHelper)
     VERSION = { "http://allmydata.org/tahoe/protocols/helper/chk-upload/v1" :
                  { },
                 "application-version": str(allmydata.__full_version__),
@@ -447,8 +447,8 @@ class CHKCiphertextFetcher(AskUntilSuccessMixin):
         return self._ciphertext_fetched
 
 
+@implementer(interfaces.IEncryptedUploadable)
 class LocalCiphertextReader(AskUntilSuccessMixin):
-    implements(interfaces.IEncryptedUploadable)
 
     def __init__(self, upload_helper, storage_index, encoding_file):
         self._readers = []
@@ -484,8 +484,8 @@ class LocalCiphertextReader(AskUntilSuccessMixin):
 
 
 
+@implementer(interfaces.RIHelper, interfaces.IStatsProducer)
 class Helper(Referenceable):
-    implements(interfaces.RIHelper, interfaces.IStatsProducer)
     # this is the non-distributed version. When we need to have multiple
     # helpers, this object will become the HelperCoordinator, and will query
     # the farm of Helpers to see if anyone has the storage_index of interest,
diff --git a/src/allmydata/immutable/repairer.py b/src/allmydata/immutable/repairer.py
index 320dbd8c4..97fc9df1b 100644
--- a/src/allmydata/immutable/repairer.py
+++ b/src/allmydata/immutable/repairer.py
@@ -1,4 +1,4 @@
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from allmydata.storage.server import si_b2a
 from allmydata.util import log, consumer
@@ -7,8 +7,8 @@ from allmydata.interfaces import IEncryptedUploadable
 
 from allmydata.immutable import upload
 
+@implementer(IEncryptedUploadable)
 class Repairer(log.PrefixingLogMixin):
-    implements(IEncryptedUploadable)
     """I generate any shares which were not available and upload them to
     servers.
 
diff --git a/src/allmydata/immutable/upload.py b/src/allmydata/immutable/upload.py
index d7a7365a6..6f5224942 100644
--- a/src/allmydata/immutable/upload.py
+++ b/src/allmydata/immutable/upload.py
@@ -1,5 +1,5 @@
 import os, time, weakref, itertools
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.python import failure
 from twisted.internet import defer
 from twisted.application import service
@@ -57,8 +57,8 @@ class HelperUploadResults(Copyable, RemoteCopy):
         self.preexisting_shares = None # count of shares already present
         self.pushed_shares = None # count of shares we pushed
 
-class UploadResults:
-    implements(IUploadResults)
+@implementer(IUploadResults)
+class UploadResults(object):
 
     def __init__(self, file_size,
                  ciphertext_fetched, # how much the helper fetched
@@ -617,10 +617,10 @@ class Tahoe2ServerSelector(log.PrefixingLogMixin):
         raise UploadUnhappinessError(msg)
 
 
-class EncryptAnUploadable:
+@implementer(IEncryptedUploadable)
+class EncryptAnUploadable(object):
     """This is a wrapper that takes an IUploadable and provides
     IEncryptedUploadable."""
-    implements(IEncryptedUploadable)
     CHUNKSIZE = 50*1024
 
     def __init__(self, original, log_parent=None, progress=None):
@@ -844,8 +844,8 @@ class EncryptAnUploadable:
     def close(self):
         return self.original.close()
 
-class UploadStatus:
-    implements(IUploadStatus)
+@implementer(IUploadStatus)
+class UploadStatus(object):
     statusid_counter = itertools.count(0)
 
     def __init__(self):
@@ -1129,8 +1129,8 @@ class LiteralUploader:
     def get_upload_status(self):
         return self._status
 
+@implementer(RIEncryptedUploadable)
 class RemoteEncryptedUploadable(Referenceable):
-    implements(RIEncryptedUploadable)
 
     def __init__(self, encrypted_uploadable, upload_status):
         self._eu = IEncryptedUploadable(encrypted_uploadable)
@@ -1407,8 +1407,8 @@ class BaseUploadable:
         d.addCallback(_got_size)
         return d
 
+@implementer(IUploadable)
 class FileHandle(BaseUploadable):
-    implements(IUploadable)
 
     def __init__(self, filehandle, convergence):
         """
@@ -1510,11 +1510,11 @@ class Data(FileHandle):
         assert convergence is None or isinstance(convergence, str), (convergence, type(convergence))
         FileHandle.__init__(self, StringIO(data), convergence=convergence)
 
+@implementer(IUploader)
 class Uploader(service.MultiService, log.PrefixingLogMixin):
     """I am a service that allows file uploading. I am a service-child of the
     Client.
     """
-    implements(IUploader)
     name = "uploader"
     URI_LIT_SIZE_THRESHOLD = 55
 
diff --git a/src/allmydata/introducer/client.py b/src/allmydata/introducer/client.py
index cc3b3dadb..a22c46103 100644
--- a/src/allmydata/introducer/client.py
+++ b/src/allmydata/introducer/client.py
@@ -1,6 +1,6 @@
 
 import time
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.application import service
 from foolscap.api import Referenceable, eventually
 from allmydata.interfaces import InsufficientVersionError
@@ -18,8 +18,8 @@ class InvalidCacheError(Exception):
 
 V2 = "http://allmydata.org/tahoe/protocols/introducer/v2"
 
+@implementer(RIIntroducerSubscriberClient_v2, IIntroducerClient)
 class IntroducerClient(service.Service, Referenceable):
-    implements(RIIntroducerSubscriberClient_v2, IIntroducerClient)
 
     def __init__(self, tub, introducer_furl,
                  nickname, my_version, oldest_supported,
diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index e999fc098..2ef68d37d 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -1,6 +1,6 @@
 
 import time, os.path, textwrap
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.application import service
 from foolscap.api import Referenceable
 import allmydata
@@ -69,8 +69,8 @@ class IntroducerNode(node.Node):
         ws = IntroducerWebishServer(self, webport, nodeurl_path, staticdir)
         self.add_service(ws)
 
+@implementer(RIIntroducerPublisherAndSubscriberService_v2)
 class IntroducerService(service.MultiService, Referenceable):
-    implements(RIIntroducerPublisherAndSubscriberService_v2)
     name = "introducer"
     # v1 is the original protocol, added in 1.0 (but only advertised starting
     # in 1.3), removed in 1.12. v2 is the new signed protocol, added in 1.10
diff --git a/src/allmydata/monitor.py b/src/allmydata/monitor.py
index d17833118..98c463014 100644
--- a/src/allmydata/monitor.py
+++ b/src/allmydata/monitor.py
@@ -1,5 +1,5 @@
 
-from zope.interface import Interface, implements
+from zope.interface import Interface, implementer
 from allmydata.util import observer
 
 class IMonitor(Interface):
@@ -80,8 +80,8 @@ class OperationCancelledError(Exception):
     pass
 
 
-class Monitor:
-    implements(IMonitor)
+@implementer(IMonitor)
+class Monitor(object):
 
     def __init__(self):
         self.cancelled = False
diff --git a/src/allmydata/mutable/filenode.py b/src/allmydata/mutable/filenode.py
index 084c28f66..bcb62eb0d 100644
--- a/src/allmydata/mutable/filenode.py
+++ b/src/allmydata/mutable/filenode.py
@@ -1,7 +1,7 @@
 
 import random
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer, reactor
 from foolscap.api import eventually
 from allmydata.interfaces import IMutableFileNode, ICheckable, ICheckResults, \
@@ -48,8 +48,8 @@ class BackoffAgent:
 
 # use nodemaker.create_mutable_file() to make one of these
 
-class MutableFileNode:
-    implements(IMutableFileNode, ICheckable)
+@implementer(IMutableFileNode, ICheckable)
+class MutableFileNode(object):
 
     def __init__(self, storage_broker, secret_holder,
                  default_encoding_parameters, history):
@@ -695,7 +695,8 @@ class MutableFileNode:
         return res
 
 
-class MutableFileVersion:
+@implementer(IMutableFileVersion, IWriteable)
+class MutableFileVersion(object):
     """
     I represent a specific version (most likely the best version) of a
     mutable file.
@@ -708,7 +709,6 @@ class MutableFileVersion:
     overwrite or modify the contents of the mutable file that I
     reference.
     """
-    implements(IMutableFileVersion, IWriteable)
 
     def __init__(self,
                  node,
diff --git a/src/allmydata/mutable/layout.py b/src/allmydata/mutable/layout.py
index 40fd9331b..dbfde5f68 100644
--- a/src/allmydata/mutable/layout.py
+++ b/src/allmydata/mutable/layout.py
@@ -7,7 +7,7 @@ from allmydata.interfaces import HASH_SIZE, SALT_SIZE, SDMF_VERSION, \
 from allmydata.util import mathutil
 from twisted.python import failure
 from twisted.internet import defer
-from zope.interface import implements
+from zope.interface import implementer
 
 
 # These strings describe the format of the packed structs they help process.
@@ -218,8 +218,8 @@ def pack_prefix(seqnum, root_hash, IV,
     return prefix
 
 
-class SDMFSlotWriteProxy:
-    implements(IMutableSlotWriter)
+@implementer(IMutableSlotWriter)
+class SDMFSlotWriteProxy(object):
     """
     I represent a remote write slot for an SDMF mutable file. I build a
     share in memory, and then write it in one piece to the remote
@@ -566,8 +566,8 @@ VERIFICATION_KEY_SIZE = 292
 # bound. Each node requires 2 bytes of node-number plus 32 bytes of hash.
 SHARE_HASH_CHAIN_SIZE = (2+HASH_SIZE)*mathutil.log_ceil(256, 2)
 
-class MDMFSlotWriteProxy:
-    implements(IMutableSlotWriter)
+@implementer(IMutableSlotWriter)
+class MDMFSlotWriteProxy(object):
 
     """
     I represent a remote write slot for an MDMF mutable file.
diff --git a/src/allmydata/mutable/publish.py b/src/allmydata/mutable/publish.py
index 88e95e6c3..4dbbd832a 100644
--- a/src/allmydata/mutable/publish.py
+++ b/src/allmydata/mutable/publish.py
@@ -3,7 +3,7 @@
 import os, time
 from StringIO import StringIO
 from itertools import count
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.python import failure
 from allmydata.interfaces import IPublishStatus, SDMF_VERSION, MDMF_VERSION, \
@@ -30,8 +30,8 @@ PUSHING_BLOCKS_STATE = 0
 PUSHING_EVERYTHING_ELSE_STATE = 1
 DONE_STATE = 2
 
-class PublishStatus:
-    implements(IPublishStatus)
+@implementer(IPublishStatus)
+class PublishStatus(object):
     statusid_counter = count(0)
     def __init__(self):
         self.timings = {}
@@ -1199,12 +1199,12 @@ class Publish:
         eventually(self.done_deferred.callback, f)
 
 
-class MutableFileHandle:
+@implementer(IMutableUploadable)
+class MutableFileHandle(object):
     """
     I am a mutable uploadable built around a filehandle-like object,
     usually either a StringIO instance or a handle to an actual file.
     """
-    implements(IMutableUploadable)
 
     def __init__(self, filehandle):
         # The filehandle is defined as a generally file-like object that
@@ -1283,13 +1283,13 @@ class MutableData(MutableFileHandle):
         MutableFileHandle.__init__(self, StringIO(s))
 
 
-class TransformingUploadable:
+@implementer(IMutableUploadable)
+class TransformingUploadable(object):
     """
     I am an IMutableUploadable that wraps another IMutableUploadable,
     and some segments that are already on the grid. When I am called to
     read, I handle merging of boundary segments.
     """
-    implements(IMutableUploadable)
 
 
     def __init__(self, data, offset, segment_size, start, end):
diff --git a/src/allmydata/mutable/repairer.py b/src/allmydata/mutable/repairer.py
index 1ec80ce20..2f9377fc7 100644
--- a/src/allmydata/mutable/repairer.py
+++ b/src/allmydata/mutable/repairer.py
@@ -1,13 +1,13 @@
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from allmydata.interfaces import IRepairResults, ICheckResults
 from allmydata.mutable.publish import MutableData
 from allmydata.mutable.common import MODE_REPAIR
 from allmydata.mutable.servermap import ServerMap, ServermapUpdater
 
-class RepairResults:
-    implements(IRepairResults)
+@implementer(IRepairResults)
+class RepairResults(object):
 
     def __init__(self, smap):
         self.servermap = smap
diff --git a/src/allmydata/mutable/retrieve.py b/src/allmydata/mutable/retrieve.py
index 9d3038aed..03dc6f888 100644
--- a/src/allmydata/mutable/retrieve.py
+++ b/src/allmydata/mutable/retrieve.py
@@ -1,7 +1,7 @@
 
 import time
 from itertools import count
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.python import failure
 from twisted.internet.interfaces import IPushProducer, IConsumer
@@ -22,8 +22,8 @@ from allmydata.mutable.common import CorruptShareError, BadShareError, \
      UncoordinatedWriteError
 from allmydata.mutable.layout import MDMFSlotReadProxy
 
-class RetrieveStatus:
-    implements(IRetrieveStatus)
+@implementer(IRetrieveStatus)
+class RetrieveStatus(object):
     statusid_counter = count(0)
     def __init__(self):
         self.timings = {}
@@ -92,13 +92,13 @@ class RetrieveStatus:
 class Marker:
     pass
 
-class Retrieve:
+@implementer(IPushProducer)
+class Retrieve(object):
     # this class is currently single-use. Eventually (in MDMF) we will make
     # it multi-use, in which case you can call download(range) multiple
     # times, and each will have a separate response chain. However the
     # Retrieve object will remain tied to a specific version of the file, and
     # will use a single ServerMap instance.
-    implements(IPushProducer)
 
     def __init__(self, filenode, storage_broker, servermap, verinfo,
                  fetch_privkey=False, verify=False):
diff --git a/src/allmydata/mutable/servermap.py b/src/allmydata/mutable/servermap.py
index 84ac1b5a5..273e0f0de 100644
--- a/src/allmydata/mutable/servermap.py
+++ b/src/allmydata/mutable/servermap.py
@@ -1,6 +1,6 @@
 
 import sys, time, copy
-from zope.interface import implements
+from zope.interface import implementer
 from itertools import count
 from twisted.internet import defer
 from twisted.python import failure
@@ -16,8 +16,8 @@ from allmydata.mutable.common import MODE_CHECK, MODE_ANYTHING, MODE_WRITE, \
      MODE_READ, MODE_REPAIR, CorruptShareError
 from allmydata.mutable.layout import SIGNED_PREFIX_LENGTH, MDMFSlotReadProxy
 
-class UpdateStatus:
-    implements(IServermapUpdaterStatus)
+@implementer(IServermapUpdaterStatus)
+class UpdateStatus(object):
     statusid_counter = count(0)
     def __init__(self):
         self.timings = {}
diff --git a/src/allmydata/nodemaker.py b/src/allmydata/nodemaker.py
index d0c002461..89fa34a6c 100644
--- a/src/allmydata/nodemaker.py
+++ b/src/allmydata/nodemaker.py
@@ -1,5 +1,5 @@
 import weakref
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata.util.assertutil import precondition
 from allmydata.interfaces import INodeMaker
 from allmydata.immutable.literal import LiteralFileNode
@@ -13,8 +13,8 @@ from allmydata.blacklist import ProhibitedNode
 from allmydata import uri
 
 
-class NodeMaker:
-    implements(INodeMaker)
+@implementer(INodeMaker)
+class NodeMaker(object):
 
     def __init__(self, storage_broker, secret_holder, history,
                  uploader, terminator,
diff --git a/src/allmydata/stats.py b/src/allmydata/stats.py
index e107c5042..19f10eb38 100644
--- a/src/allmydata/stats.py
+++ b/src/allmydata/stats.py
@@ -8,15 +8,15 @@ from collections import deque
 from twisted.internet import reactor
 from twisted.application import service
 from twisted.application.internet import TimerService
-from zope.interface import implements
+from zope.interface import implementer
 from foolscap.api import eventually, DeadReferenceError, Referenceable, Tub
 
 from allmydata.util import log
 from allmydata.util.encodingutil import quote_local_unicode_path
 from allmydata.interfaces import RIStatsProvider, RIStatsGatherer, IStatsProducer
 
+@implementer(IStatsProducer)
 class LoadMonitor(service.MultiService):
-    implements(IStatsProducer)
 
     loop_interval = 1
     num_samples = 60
@@ -69,8 +69,8 @@ class LoadMonitor(service.MultiService):
         return { 'load_monitor.avg_load': avg,
                  'load_monitor.max_load': m_x, }
 
+@implementer(IStatsProducer)
 class CPUUsageMonitor(service.MultiService):
-    implements(IStatsProducer)
     HISTORY_LENGTH = 15
     POLL_INTERVAL = 60
 
@@ -122,8 +122,8 @@ class CPUUsageMonitor(service.MultiService):
         return s
 
 
+@implementer(RIStatsProvider)
 class StatsProvider(Referenceable, service.MultiService):
-    implements(RIStatsProvider)
 
     def __init__(self, node, gatherer_furl):
         service.MultiService.__init__(self)
@@ -175,8 +175,8 @@ class StatsProvider(Referenceable, service.MultiService):
         gatherer.callRemoteOnly('provide', self, nickname or '')
 
 
+@implementer(RIStatsGatherer)
 class StatsGatherer(Referenceable, service.MultiService):
-    implements(RIStatsGatherer)
 
     poll_interval = 60
 
diff --git a/src/allmydata/storage/immutable.py b/src/allmydata/storage/immutable.py
index 280dff397..fd846c63f 100644
--- a/src/allmydata/storage/immutable.py
+++ b/src/allmydata/storage/immutable.py
@@ -2,7 +2,7 @@ import os, stat, struct, time
 
 from foolscap.api import Referenceable
 
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata.interfaces import RIBucketWriter, RIBucketReader
 from allmydata.util import base32, fileutil, log
 from allmydata.util.assertutil import precondition
@@ -194,8 +194,8 @@ class ShareFile:
         return space_freed
 
 
+@implementer(RIBucketWriter)
 class BucketWriter(Referenceable):
-    implements(RIBucketWriter)
 
     def __init__(self, ss, incominghome, finalhome, max_size, lease_info, canary):
         self.ss = ss
@@ -293,8 +293,8 @@ class BucketWriter(Referenceable):
         self.ss.bucket_writer_closed(self, 0)
 
 
+@implementer(RIBucketReader)
 class BucketReader(Referenceable):
-    implements(RIBucketReader)
 
     def __init__(self, ss, sharefname, storage_index=None, shnum=None):
         self.ss = ss
diff --git a/src/allmydata/storage/server.py b/src/allmydata/storage/server.py
index 1de4b22fe..ac5567a30 100644
--- a/src/allmydata/storage/server.py
+++ b/src/allmydata/storage/server.py
@@ -3,7 +3,7 @@ import os, re, weakref, struct, time
 from foolscap.api import Referenceable
 from twisted.application import service
 
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata.interfaces import RIStorageServer, IStatsProducer
 from allmydata.util import fileutil, idlib, log, time_format
 import allmydata # for __full_version__
@@ -33,8 +33,8 @@ NUM_RE=re.compile("^[0-9]+$")
 
 
 
+@implementer(RIStorageServer, IStatsProducer)
 class StorageServer(service.MultiService, Referenceable):
-    implements(RIStorageServer, IStatsProducer)
     name = 'storage'
     LeaseCheckerClass = LeaseCheckingCrawler
 
diff --git a/src/allmydata/storage_client.py b/src/allmydata/storage_client.py
index 8c3854225..65c65f535 100644
--- a/src/allmydata/storage_client.py
+++ b/src/allmydata/storage_client.py
@@ -30,7 +30,7 @@ the foolscap-based server implemented in src/allmydata/storage/*.py .
 
 
 import re, time, hashlib
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.application import service
 
@@ -59,8 +59,8 @@ from allmydata.util.hashutil import permute_server_hash
 #  don't pass signatures: only pass validated blessed-objects
 
 
+@implementer(IStorageBroker)
 class StorageFarmBroker(service.MultiService):
-    implements(IStorageBroker)
     """I live on the client, and know about storage servers. For each server
     that is participating in a grid, I either maintain a connection to it or
     remember enough information to establish a connection to it on demand.
@@ -235,8 +235,8 @@ class StorageFarmBroker(service.MultiService):
                     return s
         return StubServer(serverid)
 
-class StubServer:
-    implements(IDisplayableServer)
+@implementer(IDisplayableServer)
+class StubServer(object):
     def __init__(self, serverid):
         self.serverid = serverid # binary tubid
     def get_serverid(self):
@@ -248,6 +248,7 @@ class StubServer:
     def get_nickname(self):
         return "?"
 
+@implementer(IServer)
 class NativeStorageServer(service.MultiService):
     """I hold information about a storage server that we want to connect to.
     If we are connected, I hold the RemoteReference, their host address, and
@@ -263,7 +264,6 @@ class NativeStorageServer(service.MultiService):
     @ivar rref: the RemoteReference, if connected, otherwise None
     @ivar remote_host: the IAddress, if connected, otherwise None
     """
-    implements(IServer)
 
     VERSION_DEFAULTS = {
         "http://allmydata.org/tahoe/protocols/storage/v1" :
diff --git a/src/allmydata/test/bench_dirnode.py b/src/allmydata/test/bench_dirnode.py
index aecd06ce7..8626faf07 100644
--- a/src/allmydata/test/bench_dirnode.py
+++ b/src/allmydata/test/bench_dirnode.py
@@ -2,14 +2,14 @@ import hotshot.stats, os, random, sys
 
 from pyutil import benchutil, randutil # http://tahoe-lafs.org/trac/pyutil
 
-from zope.interface import implements
+from zope.interface import implementer
 from allmydata import dirnode, uri
 from allmydata.interfaces import IFileNode
 from allmydata.mutable.filenode import MutableFileNode
 from allmydata.immutable.filenode import ImmutableFileNode
 
-class ContainerNode:
-    implements(IFileNode)
+@implementer(IFileNode)
+class ContainerNode(object):
     # dirnodes sit on top of a "container" filenode, from which it extracts a
     # writekey
     def __init__(self):
diff --git a/src/allmydata/test/common.py b/src/allmydata/test/common.py
index 1979023fe..3ad3ef3d1 100644
--- a/src/allmydata/test/common.py
+++ b/src/allmydata/test/common.py
@@ -1,5 +1,5 @@
 import os, random, struct
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.internet.interfaces import IPullProducer
 from twisted.python import failure
@@ -24,15 +24,15 @@ from allmydata.immutable.upload import Uploader
 
 TEST_RSA_KEY_SIZE = 522
 
-class DummyProducer:
-    implements(IPullProducer)
+@implementer(IPullProducer)
+class DummyProducer(object):
     def resumeProducing(self):
         pass
 
+@implementer(IImmutableFileNode)
 class FakeCHKFileNode:
     """I provide IImmutableFileNode, but all of my data is stored in a
     class-level dictionary."""
-    implements(IImmutableFileNode)
 
     def __init__(self, filecap, all_contents):
         precondition(isinstance(filecap, (uri.CHKFileURI, uri.LiteralFileURI)), filecap)
@@ -167,11 +167,11 @@ def create_chk_filenode(contents, all_contents):
     return n
 
 
+@implementer(IMutableFileNode, ICheckable)
 class FakeMutableFileNode:
     """I provide IMutableFileNode, but all of my data is stored in a
     class-level dictionary."""
 
-    implements(IMutableFileNode, ICheckable)
     MUTABLE_SIZELIMIT = 10000
 
     def __init__(self, storage_broker, secret_holder,
diff --git a/src/allmydata/test/no_network.py b/src/allmydata/test/no_network.py
index 56ccfa5a9..55bd7cdb8 100644
--- a/src/allmydata/test/no_network.py
+++ b/src/allmydata/test/no_network.py
@@ -14,7 +14,7 @@
 # control.furl .
 
 import os
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.application import service
 from twisted.internet import defer, reactor
 from twisted.python.failure import Failure
@@ -130,8 +130,8 @@ def wrap_storage_server(original):
     wrapper.version = original.remote_get_version()
     return wrapper
 
-class NoNetworkServer:
-    implements(IServer)
+@implementer(IServer)
+class NoNetworkServer(object):
     def __init__(self, serverid, rref):
         self.serverid = serverid
         self.rref = rref
@@ -164,8 +164,8 @@ class NoNetworkServer:
     def get_version(self):
         return self.rref.version
 
-class NoNetworkStorageBroker:
-    implements(IStorageBroker)
+@implementer(IStorageBroker)
+class NoNetworkStorageBroker(object):
     def get_servers_for_psi(self, peer_selection_index):
         def _permuted(server):
             seed = server.get_permutation_seed()
diff --git a/src/allmydata/test/test_dirnode.py b/src/allmydata/test/test_dirnode.py
index 69def6406..ef155f8bb 100644
--- a/src/allmydata/test/test_dirnode.py
+++ b/src/allmydata/test/test_dirnode.py
@@ -2,7 +2,7 @@
 
 import time
 import unicodedata
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.trial import unittest
 from twisted.internet import defer
 from twisted.internet.interfaces import IConsumer
@@ -27,8 +27,8 @@ from allmydata.nodemaker import NodeMaker
 from base64 import b32decode
 import allmydata.test.common_util as testutil
 
-class MemAccum:
-    implements(IConsumer)
+@implementer(IConsumer)
+class MemAccum(object):
     def registerProducer(self, producer, streaming):
         self.producer = producer
         self.producer.resumeProducing()
@@ -1489,8 +1489,8 @@ class Packing(testutil.ReallyEqualMixin, unittest.TestCase):
                               dirnode.pack_children,
                               kids, fn.get_writekey(), deep_immutable=True)
 
-class FakeMutableFile:
-    implements(IMutableFileNode)
+@implementer(IMutableFileNode)
+class FakeMutableFile(object):
     counter = 0
     def __init__(self, initial_contents=""):
         data = self._get_initial_contents(initial_contents)
diff --git a/src/allmydata/test/test_encode.py b/src/allmydata/test/test_encode.py
index c908e9749..4b3bb7a0c 100644
--- a/src/allmydata/test/test_encode.py
+++ b/src/allmydata/test/test_encode.py
@@ -1,4 +1,4 @@
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.trial import unittest
 from twisted.internet import defer
 from twisted.python.failure import Failure
@@ -17,8 +17,8 @@ class LostPeerError(Exception):
 def flip_bit(good): # flips the last bit
     return good[:-1] + chr(ord(good[-1]) ^ 0x01)
 
-class FakeBucketReaderWriterProxy:
-    implements(IStorageBucketWriter, IStorageBucketReader)
+@implementer(IStorageBucketWriter, IStorageBucketReader)
+class FakeBucketReaderWriterProxy(object):
     # these are used for both reading and writing
     def __init__(self, mode="good", peerid="peer"):
         self.mode = mode
diff --git a/src/allmydata/unknown.py b/src/allmydata/unknown.py
index a8b108eea..6c970e484 100644
--- a/src/allmydata/unknown.py
+++ b/src/allmydata/unknown.py
@@ -1,5 +1,5 @@
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from allmydata.interfaces import IFilesystemNode, MustNotBeUnknownRWError, \
     MustBeDeepImmutableError
@@ -26,8 +26,8 @@ def strip_prefix_for_ro(ro_uri, deep_immutable):
     else:
         return ro_uri
 
-class UnknownNode:
-    implements(IFilesystemNode)
+@implementer(IFilesystemNode)
+class UnknownNode(object):
 
     def __init__(self, given_rw_uri, given_ro_uri, deep_immutable=False,
                  name=u"<unknown name>"):
diff --git a/src/allmydata/uri.py b/src/allmydata/uri.py
index 4d6db4829..f4f1b1542 100644
--- a/src/allmydata/uri.py
+++ b/src/allmydata/uri.py
@@ -1,7 +1,7 @@
 
 import re
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.python.components import registerAdapter
 
 from allmydata.storage.server import si_a2b, si_b2a
@@ -30,7 +30,7 @@ BASE32STR_256bits = '(%s{51}%s)' % (base32.BASE32CHAR, base32.BASE32CHAR_1bits)
 NUMBER='([0-9]+)'
 
 
-class _BaseURI:
+class _BaseURI(object):
     def __hash__(self):
         return self.to_string().__hash__()
 
@@ -50,8 +50,8 @@ class _BaseURI:
         return self.storage_index
 
 
+@implementer(IURI, IImmutableFileURI)
 class CHKFileURI(_BaseURI):
-    implements(IURI, IImmutableFileURI)
 
     BASE_STRING='URI:CHK:'
     STRING_RE=re.compile('^URI:CHK:'+BASE32STR_128bits+':'+
@@ -109,8 +109,8 @@ class CHKFileURI(_BaseURI):
                                   size=self.size)
 
 
+@implementer(IVerifierURI)
 class CHKFileVerifierURI(_BaseURI):
-    implements(IVerifierURI)
 
     BASE_STRING='URI:CHK-Verifier:'
     STRING_RE=re.compile('^URI:CHK-Verifier:'+BASE32STR_128bits+':'+
@@ -158,8 +158,8 @@ class CHKFileVerifierURI(_BaseURI):
         return self
 
 
+@implementer(IURI, IImmutableFileURI)
 class LiteralFileURI(_BaseURI):
-    implements(IURI, IImmutableFileURI)
 
     BASE_STRING='URI:LIT:'
     STRING_RE=re.compile('^URI:LIT:'+base32.BASE32STR_anybytes+'$')
@@ -199,8 +199,8 @@ class LiteralFileURI(_BaseURI):
         return len(self.data)
 
 
+@implementer(IURI, IMutableFileURI)
 class WriteableSSKFileURI(_BaseURI):
-    implements(IURI, IMutableFileURI)
 
     BASE_STRING='URI:SSK:'
     STRING_RE=re.compile('^'+BASE_STRING+BASE32STR_128bits+':'+
@@ -248,8 +248,8 @@ class WriteableSSKFileURI(_BaseURI):
         return SSKVerifierURI(self.storage_index, self.fingerprint)
 
 
+@implementer(IURI, IMutableFileURI)
 class ReadonlySSKFileURI(_BaseURI):
-    implements(IURI, IMutableFileURI)
 
     BASE_STRING='URI:SSK-RO:'
     STRING_RE=re.compile('^URI:SSK-RO:'+BASE32STR_128bits+':'+BASE32STR_256bits+'$')
@@ -295,8 +295,8 @@ class ReadonlySSKFileURI(_BaseURI):
         return SSKVerifierURI(self.storage_index, self.fingerprint)
 
 
+@implementer(IVerifierURI)
 class SSKVerifierURI(_BaseURI):
-    implements(IVerifierURI)
 
     BASE_STRING='URI:SSK-Verifier:'
     STRING_RE=re.compile('^'+BASE_STRING+BASE32STR_128bits+':'+BASE32STR_256bits+'$')
@@ -332,8 +332,8 @@ class SSKVerifierURI(_BaseURI):
         return self
 
 
+@implementer(IURI, IMutableFileURI)
 class WriteableMDMFFileURI(_BaseURI):
-    implements(IURI, IMutableFileURI)
 
     BASE_STRING='URI:MDMF:'
     STRING_RE=re.compile('^'+BASE_STRING+BASE32STR_128bits+':'+BASE32STR_256bits+'(:|$)')
@@ -381,8 +381,8 @@ class WriteableMDMFFileURI(_BaseURI):
         return MDMFVerifierURI(self.storage_index, self.fingerprint)
 
 
+@implementer(IURI, IMutableFileURI)
 class ReadonlyMDMFFileURI(_BaseURI):
-    implements(IURI, IMutableFileURI)
 
     BASE_STRING='URI:MDMF-RO:'
     STRING_RE=re.compile('^' +BASE_STRING+BASE32STR_128bits+':'+BASE32STR_256bits+'(:|$)')
@@ -430,8 +430,8 @@ class ReadonlyMDMFFileURI(_BaseURI):
         return MDMFVerifierURI(self.storage_index, self.fingerprint)
 
 
+@implementer(IVerifierURI)
 class MDMFVerifierURI(_BaseURI):
-    implements(IVerifierURI)
 
     BASE_STRING='URI:MDMF-Verifier:'
     STRING_RE=re.compile('^'+BASE_STRING+BASE32STR_128bits+':'+BASE32STR_256bits+'(:|$)')
@@ -468,8 +468,8 @@ class MDMFVerifierURI(_BaseURI):
         return self
 
 
+@implementer(IURI, IDirnodeURI)
 class _DirectoryBaseURI(_BaseURI):
-    implements(IURI, IDirnodeURI)
     def __init__(self, filenode_uri=None):
         self._filenode_uri = filenode_uri
 
@@ -515,8 +515,8 @@ class _DirectoryBaseURI(_BaseURI):
         return self._filenode_uri.get_storage_index()
 
 
+@implementer(IDirectoryURI)
 class DirectoryURI(_DirectoryBaseURI):
-    implements(IDirectoryURI)
 
     BASE_STRING='URI:DIR2:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -534,8 +534,8 @@ class DirectoryURI(_DirectoryBaseURI):
         return ReadonlyDirectoryURI(self._filenode_uri.get_readonly())
 
 
+@implementer(IReadonlyDirectoryURI)
 class ReadonlyDirectoryURI(_DirectoryBaseURI):
-    implements(IReadonlyDirectoryURI)
 
     BASE_STRING='URI:DIR2-RO:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -590,8 +590,8 @@ class LiteralDirectoryURI(_ImmutableDirectoryBaseURI):
         return None
 
 
+@implementer(IDirectoryURI)
 class MDMFDirectoryURI(_DirectoryBaseURI):
-    implements(IDirectoryURI)
 
     BASE_STRING='URI:DIR2-MDMF:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -612,8 +612,8 @@ class MDMFDirectoryURI(_DirectoryBaseURI):
         return MDMFDirectoryURIVerifier(self._filenode_uri.get_verify_cap())
 
 
+@implementer(IReadonlyDirectoryURI)
 class ReadonlyMDMFDirectoryURI(_DirectoryBaseURI):
-    implements(IReadonlyDirectoryURI)
 
     BASE_STRING='URI:DIR2-MDMF-RO:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -650,8 +650,8 @@ def wrap_dirnode_cap(filecap):
     raise AssertionError("cannot interpret as a directory cap: %s" % filecap.__class__)
 
 
+@implementer(IVerifierURI)
 class MDMFDirectoryURIVerifier(_DirectoryBaseURI):
-    implements(IVerifierURI)
 
     BASE_STRING='URI:DIR2-MDMF-Verifier:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -675,8 +675,8 @@ class MDMFDirectoryURIVerifier(_DirectoryBaseURI):
         return self
 
 
+@implementer(IVerifierURI)
 class DirectoryURIVerifier(_DirectoryBaseURI):
-    implements(IVerifierURI)
 
     BASE_STRING='URI:DIR2-Verifier:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
@@ -700,8 +700,8 @@ class DirectoryURIVerifier(_DirectoryBaseURI):
         return self
 
 
+@implementer(IVerifierURI)
 class ImmutableDirectoryURIVerifier(DirectoryURIVerifier):
-    implements(IVerifierURI)
     BASE_STRING='URI:DIR2-CHK-Verifier:'
     BASE_STRING_RE=re.compile('^'+BASE_STRING)
     INNER_URI_CLASS=CHKFileVerifierURI
diff --git a/src/allmydata/util/connection_status.py b/src/allmydata/util/connection_status.py
index 2ea2b0cab..7cc2791b2 100644
--- a/src/allmydata/util/connection_status.py
+++ b/src/allmydata/util/connection_status.py
@@ -3,7 +3,7 @@ from zope.interface import implementer
 from ..interfaces import IConnectionStatus
 
 @implementer(IConnectionStatus)
-class ConnectionStatus:
+class ConnectionStatus(object):
     def __init__(self, connected, summary, non_connected_statuses,
                  last_connection_time, last_received_time):
         self.connected = connected
diff --git a/src/allmydata/util/consumer.py b/src/allmydata/util/consumer.py
index af0a04ad7..c41115e5e 100644
--- a/src/allmydata/util/consumer.py
+++ b/src/allmydata/util/consumer.py
@@ -3,11 +3,11 @@
 a filenode's read() method. See download_to_data() for an example of its use.
 """
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet.interfaces import IConsumer
 
-class MemoryConsumer:
-    implements(IConsumer)
+@implementer(IConsumer)
+class MemoryConsumer(object):
 
     def __init__(self, progress=None):
         self.chunks = []
diff --git a/src/allmydata/web/directory.py b/src/allmydata/web/directory.py
index 88d4a5068..2b6084a3b 100644
--- a/src/allmydata/web/directory.py
+++ b/src/allmydata/web/directory.py
@@ -2,7 +2,7 @@
 import simplejson
 import urllib
 
-from zope.interface import implements
+from zope.interface import implementer
 from twisted.internet import defer
 from twisted.internet.interfaces import IPushProducer
 from twisted.python.failure import Failure
@@ -1087,8 +1087,8 @@ class DeepStatsResults(rend.Page):
         s["finished"] = self.monitor.is_finished()
         return simplejson.dumps(s, indent=1)
 
+@implementer(IPushProducer)
 class ManifestStreamer(dirnode.DeepStats):
-    implements(IPushProducer)
 
     def __init__(self, ctx, origin):
         dirnode.DeepStats.__init__(self, origin)
@@ -1144,8 +1144,8 @@ class ManifestStreamer(dirnode.DeepStats):
         self.req.write(j+"\n")
         return ""
 
+@implementer(IPushProducer)
 class DeepCheckStreamer(dirnode.DeepStats):
-    implements(IPushProducer)
 
     def __init__(self, ctx, origin, verify, repair, add_lease):
         dirnode.DeepStats.__init__(self, origin)
diff --git a/src/allmydata/web/operations.py b/src/allmydata/web/operations.py
index 8ee9f2027..21e43c9c4 100644
--- a/src/allmydata/web/operations.py
+++ b/src/allmydata/web/operations.py
@@ -1,6 +1,6 @@
 
 import time
-from zope.interface import implements
+from zope.interface import implementer
 from nevow import rend, url, tags as T
 from nevow.inevow import IRequest
 from twisted.python.failure import Failure
@@ -18,8 +18,8 @@ DAY = 24*HOUR
 
 (MONITOR, RENDERER, WHEN_ADDED) = range(3)
 
+@implementer(IOpHandleTable)
 class OphandleTable(rend.Page, service.Service):
-    implements(IOpHandleTable)
 
     UNCOLLECTED_HANDLE_LIFETIME = 4*DAY
     COLLECTED_HANDLE_LIFETIME = 1*DAY