diff --git a/contrib/synthrepo.py b/contrib/synthrepo.py
--- a/contrib/synthrepo.py
+++ b/contrib/synthrepo.py
@@ -213,7 +213,7 @@ def analyze(ui, repo, *revs, **opts):
             for filename, mar, lineadd, lineremove, isbin in parsegitdiff(diff):
                 if isbin:
                     continue
-                added = sum(lineadd.itervalues(), 0)
+                added = sum(pycompat.itervalues(lineadd), 0)
                 if mar == 'm':
                     if added and lineremove:
                         lineschanged[
diff --git a/hgext/journal.py b/hgext/journal.py
--- a/hgext/journal.py
+++ b/hgext/journal.py
@@ -164,7 +164,7 @@ def _mergeentriesiter(*iterables, **kwar
             pass
 
     while iterable_map:
-        value, key, it = order(iterable_map.itervalues())
+        value, key, it = order(pycompat.itervalues(iterable_map))
         yield value
         try:
             iterable_map[key][0] = next(it)
diff --git a/hgext/rebase.py b/hgext/rebase.py
--- a/hgext/rebase.py
+++ b/hgext/rebase.py
@@ -2288,7 +2288,7 @@ def summaryhook(ui, repo):
         msg = _(b'rebase: (use "hg rebase --abort" to clear broken state)\n')
         ui.write(msg)
         return
-    numrebased = len([i for i in state.itervalues() if i >= 0])
+    numrebased = len([i for i in pycompat.itervalues(state) if i >= 0])
     # i18n: column positioning for "hg summary"
     ui.write(
         _(b'rebase: %s, %s (rebase --continue)\n')
diff --git a/hgext/remotefilelog/connectionpool.py b/hgext/remotefilelog/connectionpool.py
--- a/hgext/remotefilelog/connectionpool.py
+++ b/hgext/remotefilelog/connectionpool.py
@@ -10,6 +10,7 @@ from __future__ import absolute_import
 from mercurial import (
     extensions,
     hg,
+    pycompat,
     sshpeer,
     util,
 )
@@ -59,7 +60,7 @@ class connectionpool(object):
         return conn
 
     def close(self):
-        for pathpool in self._pool.itervalues():
+        for pathpool in pycompat.itervalues(self._pool):
             for conn in pathpool:
                 conn.close()
             del pathpool[:]
diff --git a/hgext/remotefilelog/debugcommands.py b/hgext/remotefilelog/debugcommands.py
--- a/hgext/remotefilelog/debugcommands.py
+++ b/hgext/remotefilelog/debugcommands.py
@@ -207,7 +207,7 @@ def verifyremotefilelog(ui, path, **opts
                 continue
             filepath = os.path.join(root, file)
             size, firstnode, mapping = parsefileblob(filepath, decompress)
-            for p1, p2, linknode, copyfrom in mapping.itervalues():
+            for p1, p2, linknode, copyfrom in pycompat.itervalues(mapping):
                 if linknode == nullid:
                     actualpath = os.path.relpath(root, path)
                     key = fileserverclient.getcachekey(
diff --git a/hgext/remotefilelog/repack.py b/hgext/remotefilelog/repack.py
--- a/hgext/remotefilelog/repack.py
+++ b/hgext/remotefilelog/repack.py
@@ -598,7 +598,7 @@ class repacker(object):
         maxchainlen = ui.configint(b'packs', b'maxchainlen', 1000)
 
         byfile = {}
-        for entry in ledger.entries.itervalues():
+        for entry in pycompat.itervalues(ledger.entries):
             if entry.datasource:
                 byfile.setdefault(entry.filename, {})[entry.node] = entry
 
@@ -753,7 +753,7 @@ class repacker(object):
         ui = self.repo.ui
 
         byfile = {}
-        for entry in ledger.entries.itervalues():
+        for entry in pycompat.itervalues(ledger.entries):
             if entry.historysource:
                 byfile.setdefault(entry.filename, {})[entry.node] = entry
 
diff --git a/hgext/transplant.py b/hgext/transplant.py
--- a/hgext/transplant.py
+++ b/hgext/transplant.py
@@ -100,7 +100,7 @@ class transplants(object):
             if not os.path.isdir(self.path):
                 os.mkdir(self.path)
             fp = self.opener(self.transplantfile, b'w')
-            for list in self.transplants.itervalues():
+            for list in pycompat.itervalues(self.transplants):
                 for t in list:
                     l, r = map(nodemod.hex, (t.lnode, t.rnode))
                     fp.write(l + b':' + r + b'\n')
diff --git a/mercurial/__init__.py b/mercurial/__init__.py
--- a/mercurial/__init__.py
+++ b/mercurial/__init__.py
@@ -117,7 +117,7 @@ if sys.version_info[0] >= 3:
 
                 # It changes iteritems/values to items/values as they are not
                 # present in Python 3 world.
-                if fn in ('iteritems', 'itervalues') and not (
+                if fn == 'iteritems' and not (
                     tokens[i - 1].type == token.NAME
                     and tokens[i - 1].string == 'def'
                 ):
@@ -131,7 +131,7 @@ if sys.version_info[0] >= 3:
     # ``replacetoken`` or any mechanism that changes semantics of module
     # loading is changed. Otherwise cached bytecode may get loaded without
     # the new transformation mechanisms applied.
-    BYTECODEHEADER = b'HG\x00\x14'
+    BYTECODEHEADER = b'HG\x00\x15'
 
     class hgloader(importlib.machinery.SourceFileLoader):
         """Custom module loader that transforms source code.
diff --git a/mercurial/branchmap.py b/mercurial/branchmap.py
--- a/mercurial/branchmap.py
+++ b/mercurial/branchmap.py
@@ -91,7 +91,7 @@ class BranchMapCache(object):
         clbranchinfo = cl.branchinfo
         rbheads = []
         closed = []
-        for bheads in remotebranchmap.itervalues():
+        for bheads in pycompat.itervalues(remotebranchmap):
             rbheads += bheads
             for h in bheads:
                 r = clrev(h)
@@ -350,7 +350,7 @@ class branchcache(object):
     def iterheads(self):
         """ returns all the heads """
         self._verifyall()
-        return self._entries.itervalues()
+        return pycompat.itervalues(self._entries)
 
     def copy(self):
         """return an deep copy of the branchcache object"""
diff --git a/mercurial/exchangev2.py b/mercurial/exchangev2.py
--- a/mercurial/exchangev2.py
+++ b/mercurial/exchangev2.py
@@ -607,7 +607,7 @@ def _fetchfiles(repo, tr, remote, fnodes
     progress = repo.ui.makeprogress(
         _(b'files'),
         unit=_(b'chunks'),
-        total=sum(len(v) for v in fnodes.itervalues()),
+        total=sum(len(v) for v in pycompat.itervalues(fnodes)),
     )
 
     # TODO make batch size configurable
@@ -706,7 +706,7 @@ def _fetchfilesfromcsets(
     progress = repo.ui.makeprogress(
         _(b'files'),
         unit=_(b'chunks'),
-        total=sum(len(v) for v in fnodes.itervalues()),
+        total=sum(len(v) for v in pycompat.itervalues(fnodes)),
     )
 
     commandmeta = remote.apidescriptor[b'commands'][b'filesdata']
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -1763,7 +1763,7 @@ class localrepository(object):
             nodetagscache = {}
             for t, n in self._tagscache.tags.iteritems():
                 nodetagscache.setdefault(n, []).append(t)
-            for tags in nodetagscache.itervalues():
+            for tags in pycompat.itervalues(nodetagscache):
                 tags.sort()
             self._tagscache.nodetagscache = nodetagscache
         return self._tagscache.nodetagscache.get(node, [])
diff --git a/mercurial/merge.py b/mercurial/merge.py
--- a/mercurial/merge.py
+++ b/mercurial/merge.py
@@ -702,7 +702,7 @@ class mergestate(object):
         """return counts for updated, merged and removed files in this
         session"""
         updated, merged, removed = 0, 0, 0
-        for r, action in self._results.itervalues():
+        for r, action in pycompat.itervalues(self._results):
             if r is None:
                 updated += 1
             elif r == 0:
diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -1331,7 +1331,11 @@ the hunk is left unchanged.
                 fixoffset += chunk.removed - chunk.added
     return (
         sum(
-            [h for h in applied.itervalues() if h[0].special() or len(h) > 1],
+            [
+                h
+                for h in pycompat.itervalues(applied)
+                if h[0].special() or len(h) > 1
+            ],
             [],
         ),
         {},
diff --git a/mercurial/pycompat.py b/mercurial/pycompat.py
--- a/mercurial/pycompat.py
+++ b/mercurial/pycompat.py
@@ -337,6 +337,7 @@ if ispy3:
         ret = shlex.split(s.decode('latin-1'), comments, posix)
         return [a.encode('latin-1') for a in ret]
 
+    itervalues = lambda x: x.values()
 
 else:
     import cStringIO
@@ -413,6 +414,7 @@ else:
     ziplist = zip
     rawinput = raw_input
     getargspec = inspect.getargspec
+    itervalues = lambda x: x.itervalues()
 
 isjython = sysplatform.startswith(b'java')
 
diff --git a/mercurial/statprof.py b/mercurial/statprof.py
--- a/mercurial/statprof.py
+++ b/mercurial/statprof.py
@@ -475,7 +475,7 @@ class SiteStats(object):
                 if i == 0:
                     sitestat.addself()
 
-        return [s for s in stats.itervalues()]
+        return [s for s in pycompat.itervalues(stats)]
 
 
 class DisplayFormats:
@@ -744,7 +744,7 @@ def display_hotpath(data, fp, limit=0.05
         site = node.site
         visiblechildren = [
             c
-            for c in node.children.itervalues()
+            for c in pycompat.itervalues(node.children)
             if c.count >= (limit * root.count)
         ]
         if site:
@@ -752,7 +752,7 @@ def display_hotpath(data, fp, limit=0.05
             filename = b''
             function = b''
             if len(node.children) > 0:
-                childsite = list(node.children.itervalues())[0].site
+                childsite = list(pycompat.itervalues(node.children))[0].site
                 filename = (childsite.filename() + b':').ljust(15)
                 function = childsite.function
 
@@ -777,7 +777,9 @@ def display_hotpath(data, fp, limit=0.05
             )
 
             finalstring = liststring + codestring
-            childrensamples = sum([c.count for c in node.children.itervalues()])
+            childrensamples = sum(
+                [c.count for c in pycompat.itervalues(node.children)]
+            )
             # Make frames that performed more than 10% of the operation red
             if node.count - childrensamples > (0.1 * root.count):
                 finalstring = b'\033[91m' + finalstring + b'\033[0m'
diff --git a/mercurial/ui.py b/mercurial/ui.py
--- a/mercurial/ui.py
+++ b/mercurial/ui.py
@@ -1966,7 +1966,7 @@ class ui(object):
         if not self._loggers:
             return
         activeloggers = [
-            l for l in self._loggers.itervalues() if l.tracked(event)
+            l for l in pycompat.itervalues(self._loggers) if l.tracked(event)
         ]
         if not activeloggers:
             return
diff --git a/tests/test-pathencode.py b/tests/test-pathencode.py
--- a/tests/test-pathencode.py
+++ b/tests/test-pathencode.py
@@ -67,7 +67,7 @@ def buildprobtable(fp, cmd='hg manifest 
             counts[c] += 1
     for c in '\r/\n':
         counts.pop(c, None)
-    t = sum(counts.itervalues()) / 100.0
+    t = sum(pycompat.itervalues(counts)) / 100.0
     fp.write('probtable = (')
     for i, (k, v) in enumerate(
         sorted(counts.items(), key=lambda x: x[1], reverse=True)