diff --git a/CHANGES.txt b/CHANGES.txt
index 212bc5b..3aaef4c 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,6 +1,17 @@
 Changelog
 =========
 
+2.0a1 (unreleased)
+------------------
+
+- Remove "Plone 3 only" code.
+  [timo]
+  
+- Do not monkey patch the BAD_TYPES vocabulary or plone.app.vocabularies
+  anymore.
+  [timo]
+
+
 2.0a1 (2011-02-07)
 ------------------
 
diff --git a/plone/app/discussion/__init__.py b/plone/app/discussion/__init__.py
index 2e973d9..11103ca 100644
--- a/plone/app/discussion/__init__.py
+++ b/plone/app/discussion/__init__.py
@@ -1,16 +1,4 @@
 # -*- coding: utf-8 -*-
 
 from zope.i18nmessageid import MessageFactory
-PloneAppDiscussionMessageFactory = MessageFactory('plone.app.discussion')
-
-# Monkey patch plone.app.vocabularies.types.BAD_TYPES and remove
-# 'Discussion Item' from this tuple, so that Comments can be found
-# in the search. This will become needless once plone.app.discussion
-# will become a part of Plone 4.
-
-import plone.app.vocabularies.types
-
-new_bad_types = list(plone.app.vocabularies.types.BAD_TYPES)
-if 'Discussion Item' in new_bad_types:
-    new_bad_types.remove('Discussion Item')
-plone.app.vocabularies.types.BAD_TYPES = new_bad_types
\ No newline at end of file
+PloneAppDiscussionMessageFactory = MessageFactory('plone.app.discussion')
\ No newline at end of file
diff --git a/plone/app/discussion/browser/captcha.zcml b/plone/app/discussion/browser/captcha.zcml
index 8c1f3d3..9acfddf 100644
--- a/plone/app/discussion/browser/captcha.zcml
+++ b/plone/app/discussion/browser/captcha.zcml
@@ -4,21 +4,6 @@
     xmlns:zcml="http://namespaces.zope.org/zcml"
     i18n_domain="plone.app.discussion">
 
-    <!--
-      Plone 3 fixes
-
-      Plone 3 / Zope 2.10 does not recognize the meta:provides feature.
-      Therefore we claim to provide this feature when a suitable package is
-      installed.
-    -->
-    <configure zcml:condition="installed plone.formwidget.captcha">
-        <meta:provides feature="plone.app.discussion-captcha" />
-    </configure>
-
-    <configure zcml:condition="installed plone.formwidget.recaptcha">
-        <meta:provides feature="plone.app.discussion-captcha" />
-    </configure>
-
     <!-- Captcha comment form extender -->
     <configure zcml:condition="have plone.app.discussion-captcha">
         <!--
diff --git a/plone/app/discussion/browser/moderation.py b/plone/app/discussion/browser/moderation.py
index 50dbc47..d6a1ca7 100644
--- a/plone/app/discussion/browser/moderation.py
+++ b/plone/app/discussion/browser/moderation.py
@@ -11,26 +11,6 @@ from Products.statusmessages.interfaces import IStatusMessage
 from plone.app.discussion.interfaces import _
 from plone.app.discussion.interfaces import IComment
 
-# Begin ugly hack. It works around a ContentProviderLookupError:
-# plone.htmlhead error caused by Zope 2 permissions.
-# This error occured on Plone 3.3.x only!
-#
-# Source:
-# http://athenageek.wordpress.com/2008/01/08/
-# contentproviderlookuperror-plonehtmlhead/
-#
-# Bug report: https://bugs.launchpad.net/zope2/+bug/176566
-#
-
-def _getContext(self): # pragma: no cover
-    self = self.aq_parent
-    while getattr(self, '_is_wrapperish', None):
-        self = self.aq_parent
-    return self
-
-ZopeTwoPageTemplateFile._getContext = _getContext # pragma: no cover
-# End ugly hack.
-
 
 class View(BrowserView):
     """Main moderation View.
diff --git a/plone/app/discussion/comment.py b/plone/app/discussion/comment.py
index 13d8260..f167a1d 100644
--- a/plone/app/discussion/comment.py
+++ b/plone/app/discussion/comment.py
@@ -38,19 +38,9 @@ from plone.app.discussion.interfaces import IComment
 from plone.app.discussion.interfaces import IConversation
 from plone.app.discussion.interfaces import IDiscussionSettings
 
-try:
-    # Plone 4:
-    # Mixin CatalogAware and WorkflowAware into the Comment class
-    # is necessary for comments to be indexed in Plone4.
-    from Products.CMFCore.CMFCatalogAware import CatalogAware  # pylint: disable-msg=W0611
-    from Products.CMFCore.CMFCatalogAware import WorkflowAware  # pylint: disable-msg=W0611
-    PLONE_4 = True
-except: # pragma: no cover
-    # Plone 3:
-    # Dummy imports to make Comment class happy
-    from OFS.Traversable import Traversable as CatalogAware # pylint: disable-msg=W0611
-    from OFS.Traversable import Traversable as WorkflowAware # pylint: disable-msg=W0611
-    PLONE_4 = False
+from Products.CMFCore.CMFCatalogAware import CatalogAware
+from Products.CMFCore.CMFCatalogAware import WorkflowAware
+
 
 COMMENT_TITLE = _(u"comment_title",
     default=u"${creator} on ${content}")
@@ -240,30 +230,17 @@ def notify_user(obj, event):
                         context=obj.REQUEST)
     for email in emails:
         # Send email
-        if PLONE_4:
-            try:
-                mail_host.send(message,
-                               email,
-                               sender,
-                               subject,
-                               charset='utf-8')
-            except SMTPException:
-                logger.error('SMTP exception while trying to send an ' +
-                             'email from %s to %s',
-                             sender,
-                             email)
-        else:  # pragma: no cover
-            try:
-                mail_host.secureSend(message,
-                                     email,
-                                     sender,
-                                     subject=subject,
-                                     charset='utf-8')
-            except SMTPException:
-                logger.error('SMTP exception while trying to send an ' +
-                             'email from %s to %s',
-                             sender,
-                             email)
+        try:
+            mail_host.send(message,
+                           email,
+                           sender,
+                           subject,
+                           charset='utf-8')
+        except SMTPException:
+            logger.error('SMTP exception while trying to send an ' +
+                         'email from %s to %s',
+                         sender,
+                         email)
 
 
 def notify_moderator(obj, event):
@@ -307,29 +284,13 @@ def notify_moderator(obj, event):
         context=obj.REQUEST)
 
     # Send email
-    if PLONE_4:
-        try:
-            mail_host.send(message, mto, sender, subject, charset='utf-8')
-        except SMTPException, e:
-            logger.error('SMTP exception (%s) while trying to send an ' +
-                         'email notification to the comment moderator ' +
-                         '(from %s to %s, message: %s)',
-                         e,
-                         sender,
-                         mto,
-                         message)
-    else: # pragma: no cover
-        try:
-            mail_host.secureSend(message,
-                                 mto,
-                                 sender,
-                                 subject=subject,
-                                 charset='utf-8')
-        except SMTPException, e:
-            logger.error('SMTP exception (%s) while trying to send an ' +
-                         'email notification to the comment moderator ' +
-                         '(from %s to %s, message: %s)',
-                         e,
-                         sender,
-                         mto,
-                         message)
+    try:
+        mail_host.send(message, mto, sender, subject, charset='utf-8')
+    except SMTPException, e:
+        logger.error('SMTP exception (%s) while trying to send an ' +
+                     'email notification to the comment moderator ' +
+                     '(from %s to %s, message: %s)',
+                     e,
+                     sender,
+                     mto,
+                     message)
diff --git a/plone/app/discussion/conversation.py b/plone/app/discussion/conversation.py
index 02b6506..14f2581 100644
--- a/plone/app/discussion/conversation.py
+++ b/plone/app/discussion/conversation.py
@@ -40,24 +40,13 @@ from zope.container.contained import ContainerModifiedEvent
 
 from zope.lifecycleevent import ObjectCreatedEvent
 
-try:
-    # Plone 4
-    from zope.lifecycleevent import ObjectAddedEvent
-    from zope.lifecycleevent import ObjectRemovedEvent
-except ImportError: # pragma: no cover
-    # Plone 3.x
-    from zope.app.container.contained import ObjectAddedEvent # pragma: no cover
-    from zope.app.container.contained import ObjectRemovedEvent # pragma: no cover
+from zope.lifecycleevent import ObjectAddedEvent
+from zope.lifecycleevent import ObjectRemovedEvent
 
 from BTrees.OIBTree import OIBTree
 
-try:
-    # These exist in new versions, but not in the one that comes with Zope 2.10.
-    from BTrees.LOBTree import LOBTree
-    from BTrees.LLBTree import LLSet
-except ImportError: # pragma: no cover
-    from BTrees.OOBTree import OOBTree as LOBTree # pragma: no cover
-    from BTrees.OOBTree import OOSet as LLSet # pragma: no cover
+from BTrees.LOBTree import LOBTree
+from BTrees.LLBTree import LLSet
 
 from plone.app.discussion.interfaces import IConversation
 from plone.app.discussion.interfaces import IDiscussionSettings
diff --git a/plone/app/discussion/tests/test_comment.py b/plone/app/discussion/tests/test_comment.py
index cc71759..401c9f9 100644
--- a/plone/app/discussion/tests/test_comment.py
+++ b/plone/app/discussion/tests/test_comment.py
@@ -71,15 +71,7 @@ class CommentTest(PloneTestCase):
         conversation.addComment(comment1)
         comment_brain = self.catalog.searchResults(
                             portal_type = 'Discussion Item')[0]
-
-        # comment should only have a UID if plone.uuid is present
-        try:
-            from plone.uuid.interfaces import IUUID
-            IUUID # pyflakes
-        except ImportError:
-            self.failIf(comment_brain.UID)
-        else:
-            self.failUnless(comment_brain.UID)
+        self.failUnless(comment_brain.UID)
 
     def test_uid_is_unique(self):
         conversation = IConversation(self.portal.doc1)
@@ -89,11 +81,7 @@ class CommentTest(PloneTestCase):
         conversation.addComment(comment2)
         brains = self.catalog.searchResults(
                      portal_type = 'Discussion Item')
-
-        # make sure uids are either both None (i.e. without plone.uuid),
-        # or not equal
-        if brains[0].UID != None or brains[1].UID != None:
-            self.assertNotEquals(brains[0].UID, brains[1].UID)
+        self.assertNotEquals(brains[0].UID, brains[1].UID)
 
     def test_comment_uid_differs_from_content_uid(self):
         conversation = IConversation(self.portal.doc1)
diff --git a/plone/app/discussion/tests/test_conversation.py b/plone/app/discussion/tests/test_conversation.py
index 6711169..1c7f7c2 100644
--- a/plone/app/discussion/tests/test_conversation.py
+++ b/plone/app/discussion/tests/test_conversation.py
@@ -680,14 +680,8 @@ class ConversationTest(PloneTestCase):
 
         self.assertEquals(('', 'plone', 'doc1', '++conversation++default'),
                           conversation.getPhysicalPath())
-        # XXX: conversation.absolute_url() returns different values dependent
-        # on the Plone version used.
-        # Plone 3.3:
-        #self.assertEquals('plone/doc1/%2B%2Bconversation%2B%2Bdefault',
-        #conversation.absolute_url())
-        # Plone 4:
-        #self.assertEquals('http://nohost/plone/doc1/++conversation++default',
-        #conversation.absolute_url())
+        self.assertEquals('http://nohost/plone/doc1/++conversation++default',
+                          conversation.absolute_url())
 
     def test_parent(self):
         # Check that conversation has a content object as parent
@@ -701,7 +695,6 @@ class ConversationTest(PloneTestCase):
 
         self.assertEquals(conversation.__parent__.getId(), 'doc1')
 
-
     def test_discussion_item_not_in_bad_types(self):
         self.failIf('Discussion Item' in BAD_TYPES)
 
diff --git a/plone/app/discussion/tests/test_notifications.py b/plone/app/discussion/tests/test_notifications.py
index 86b05ad..bbb4a76 100644
--- a/plone/app/discussion/tests/test_notifications.py
+++ b/plone/app/discussion/tests/test_notifications.py
@@ -214,14 +214,8 @@ class TestModeratorNotificationUnit(PloneTestCase):
         self.failUnless(self.mailhost.messages[0])
         msg = self.mailhost.messages[0]
 
-        if not isinstance(msg, str):
-            # Plone 3
-            self.failUnless('portal@plone.test' in msg.mfrom)
-            self.failUnless('portal@plone.test' in msg.mto)
-        else:
-            #Plone 4
-            self.failUnless('To: portal@plone.test' in msg)
-            self.failUnless('From: portal@plone.test' in msg)
+        self.failUnless('To: portal@plone.test' in msg)
+        self.failUnless('From: portal@plone.test' in msg)
 
         #We expect the headers to be properly header encoded (7-bit):
         #>>> 'Subject: =?utf-8?q?Some_t=C3=A4st_subject=2E?=' in msg