diff --git a/vcsserver/config/settings_maker.py b/vcsserver/config/settings_maker.py
--- a/vcsserver/config/settings_maker.py
+++ b/vcsserver/config/settings_maker.py
@@ -58,7 +58,7 @@ def aslist(obj, sep=None, strip=True):
     :param sep:
     :param strip:
     """
-    if isinstance(obj, (basestring,)):
+    if isinstance(obj, str):
         if obj in ['', ""]:
             return []
 
diff --git a/vcsserver/git_lfs/tests/test_lfs_app.py b/vcsserver/git_lfs/tests/test_lfs_app.py
--- a/vcsserver/git_lfs/tests/test_lfs_app.py
+++ b/vcsserver/git_lfs/tests/test_lfs_app.py
@@ -54,19 +54,19 @@ class TestLFSApplication(object):
     def test_app_deprecated_endpoint(self, git_lfs_app):
         response = git_lfs_app.post('/repo/info/lfs/objects', status=501)
         assert response.status_code == 501
-        assert json.loads(response.text) == {u'message': u'LFS: v1 api not supported'}
+        assert json.loads(response.text) == {'message': 'LFS: v1 api not supported'}
 
     def test_app_lock_verify_api_not_available(self, git_lfs_app):
         response = git_lfs_app.post('/repo/info/lfs/locks/verify', status=501)
         assert response.status_code == 501
         assert json.loads(response.text) == {
-            u'message': u'GIT LFS locking api not supported'}
+            'message': 'GIT LFS locking api not supported'}
 
     def test_app_lock_api_not_available(self, git_lfs_app):
         response = git_lfs_app.post('/repo/info/lfs/locks', status=501)
         assert response.status_code == 501
         assert json.loads(response.text) == {
-            u'message': u'GIT LFS locking api not supported'}
+            'message': 'GIT LFS locking api not supported'}
 
     def test_app_batch_api_missing_auth(self, git_lfs_app):
         git_lfs_app.post_json(
@@ -77,14 +77,14 @@ class TestLFSApplication(object):
             '/repo/info/lfs/objects/batch', params={}, status=400,
             extra_environ=http_auth)
         assert json.loads(response.text) == {
-            u'message': u'unsupported operation mode: `None`'}
+            'message': 'unsupported operation mode: `None`'}
 
     def test_app_batch_api_missing_objects(self, git_lfs_app, http_auth):
         response = git_lfs_app.post_json(
             '/repo/info/lfs/objects/batch', params={'operation': 'download'},
             status=400, extra_environ=http_auth)
         assert json.loads(response.text) == {
-            u'message': u'missing objects data'}
+            'message': 'missing objects data'}
 
     def test_app_batch_api_unsupported_data_in_objects(
             self, git_lfs_app, http_auth):
@@ -94,7 +94,7 @@ class TestLFSApplication(object):
             '/repo/info/lfs/objects/batch', params=params, status=400,
             extra_environ=http_auth)
         assert json.loads(response.text) == {
-            u'message': u'unsupported data in objects'}
+            'message': 'unsupported data in objects'}
 
     def test_app_batch_api_download_missing_object(
             self, git_lfs_app, http_auth):
@@ -105,12 +105,12 @@ class TestLFSApplication(object):
             extra_environ=http_auth)
 
         expected_objects = [
-            {u'authenticated': True,
-             u'errors': {u'error': {
-                 u'code': 404,
-                 u'message': u'object: 123 does not exist in store'}},
-             u'oid': u'123',
-             u'size': u'1024'}
+            {'authenticated': True,
+             'errors': {'error': {
+                 'code': 404,
+                 'message': 'object: 123 does not exist in store'}},
+             'oid': '123',
+             'size': '1024'}
         ]
         assert json.loads(response.text) == {
             'objects': expected_objects, 'transfer': 'basic'}
@@ -130,14 +130,14 @@ class TestLFSApplication(object):
             extra_environ=http_auth)
 
         expected_objects = [
-            {u'authenticated': True,
-             u'actions': {
-                 u'download': {
-                     u'header': {u'Authorization': u'Basic XXXXX'},
-                     u'href': u'http://localhost/repo/info/lfs/objects/456'},
+            {'authenticated': True,
+             'actions': {
+                 'download': {
+                     'header': {'Authorization': 'Basic XXXXX'},
+                     'href': 'http://localhost/repo/info/lfs/objects/456'},
              },
-             u'oid': u'456',
-             u'size': u'1024'}
+             'oid': '456',
+             'size': '1024'}
         ]
         assert json.loads(response.text) == {
             'objects': expected_objects, 'transfer': 'basic'}
@@ -149,18 +149,18 @@ class TestLFSApplication(object):
             '/repo/info/lfs/objects/batch', params=params,
             extra_environ=http_auth)
         expected_objects = [
-            {u'authenticated': True,
-             u'actions': {
-                 u'upload': {
-                     u'header': {u'Authorization': u'Basic XXXXX',
-                                 u'Transfer-Encoding': u'chunked'},
-                     u'href': u'http://localhost/repo/info/lfs/objects/123'},
-                 u'verify': {
-                     u'header': {u'Authorization': u'Basic XXXXX'},
-                     u'href': u'http://localhost/repo/info/lfs/verify'}
+            {'authenticated': True,
+             'actions': {
+                 'upload': {
+                     'header': {'Authorization': 'Basic XXXXX',
+                                 'Transfer-Encoding': 'chunked'},
+                     'href': 'http://localhost/repo/info/lfs/objects/123'},
+                 'verify': {
+                     'header': {'Authorization': 'Basic XXXXX'},
+                     'href': 'http://localhost/repo/info/lfs/verify'}
              },
-             u'oid': u'123',
-             u'size': u'1024'}
+             'oid': '123',
+             'size': '1024'}
         ]
         assert json.loads(response.text) == {
             'objects': expected_objects, 'transfer': 'basic'}
@@ -172,18 +172,18 @@ class TestLFSApplication(object):
             '/repo/info/lfs/objects/batch', params=params,
             extra_environ=http_auth)
         expected_objects = [
-            {u'authenticated': True,
-             u'actions': {
-                 u'upload': {
-                     u'header': {u'Authorization': u'Basic XXXXX',
-                                 u'Transfer-Encoding': u'chunked'},
-                     u'href': u'https://localhost/repo/info/lfs/objects/123'},
-                 u'verify': {
-                     u'header': {u'Authorization': u'Basic XXXXX'},
-                     u'href': u'https://localhost/repo/info/lfs/verify'}
+            {'authenticated': True,
+             'actions': {
+                 'upload': {
+                     'header': {'Authorization': 'Basic XXXXX',
+                                 'Transfer-Encoding': 'chunked'},
+                     'href': 'https://localhost/repo/info/lfs/objects/123'},
+                 'verify': {
+                     'header': {'Authorization': 'Basic XXXXX'},
+                     'href': 'https://localhost/repo/info/lfs/verify'}
              },
-             u'oid': u'123',
-             u'size': u'1024'}
+             'oid': '123',
+             'size': '1024'}
         ]
         assert json.loads(response.text) == {
             'objects': expected_objects, 'transfer': 'basic'}
@@ -195,7 +195,7 @@ class TestLFSApplication(object):
             status=400)
 
         assert json.loads(response.text) == {
-            u'message': u'missing oid and size in request data'}
+            'message': 'missing oid and size in request data'}
 
     def test_app_verify_api_missing_obj(self, git_lfs_app):
         params = {'oid': 'missing', 'size': '1024'}
@@ -204,7 +204,7 @@ class TestLFSApplication(object):
             status=404)
 
         assert json.loads(response.text) == {
-            u'message': u'oid `missing` does not exists in store'}
+            'message': 'oid `missing` does not exists in store'}
 
     def test_app_verify_api_size_mismatch(self, git_lfs_app):
         oid = 'existing'
@@ -219,8 +219,8 @@ class TestLFSApplication(object):
             '/repo/info/lfs/verify', params=params, status=422)
 
         assert json.loads(response.text) == {
-            u'message': u'requested file size mismatch '
-                        u'store size:11 requested:1024'}
+            'message': 'requested file size mismatch '
+                        'store size:11 requested:1024'}
 
     def test_app_verify_api(self, git_lfs_app):
         oid = 'existing'
@@ -235,7 +235,7 @@ class TestLFSApplication(object):
             '/repo/info/lfs/verify', params=params)
 
         assert json.loads(response.text) == {
-            u'message': {u'size': u'ok', u'in_store': u'ok'}}
+            'message': {'size': 'ok', 'in_store': 'ok'}}
 
     def test_app_download_api_oid_not_existing(self, git_lfs_app):
         oid = 'missing'
@@ -244,7 +244,7 @@ class TestLFSApplication(object):
             '/repo/info/lfs/objects/{oid}'.format(oid=oid), status=404)
 
         assert json.loads(response.text) == {
-            u'message': u'requested file with oid `missing` not found in store'}
+            'message': 'requested file with oid `missing` not found in store'}
 
     def test_app_download_api(self, git_lfs_app):
         oid = 'existing'
@@ -264,7 +264,7 @@ class TestLFSApplication(object):
         response = git_lfs_app.put(
             '/repo/info/lfs/objects/{oid}'.format(oid=oid), params='CONTENT')
 
-        assert json.loads(response.text) == {u'upload': u'ok'}
+        assert json.loads(response.text) == {'upload': 'ok'}
 
         # verify that we actually wrote that OID
         oid_path = os.path.join(git_lfs_app._store, oid)
diff --git a/vcsserver/hgcompat.py b/vcsserver/hgcompat.py
--- a/vcsserver/hgcompat.py
+++ b/vcsserver/hgcompat.py
@@ -78,7 +78,7 @@ def get_ctx(repo, ref):
         ctx = revsymbol(repo, ref)
     except (LookupError, RepoLookupError):
         # Similar case as above but only for refs that are not numeric
-        if isinstance(ref, (int, long)):
+        if isinstance(ref, int):
             raise
         ctx = revsymbol(repo, ref)
     return ctx
diff --git a/vcsserver/hooks.py b/vcsserver/hooks.py
--- a/vcsserver/hooks.py
+++ b/vcsserver/hooks.py
@@ -579,7 +579,7 @@ def git_post_receive(unused_repo_path, r
                 except Exception:
                     cmd = [settings.GIT_EXECUTABLE, 'symbolic-ref', '"HEAD"',
                            '"refs/heads/%s"' % push_ref['name']]
-                    print("Setting default branch to %s" % push_ref['name'])
+                    print(("Setting default branch to %s" % push_ref['name']))
                     subprocessio.run_command(cmd, env=os.environ.copy())
 
                 cmd = [settings.GIT_EXECUTABLE, 'for-each-ref',
diff --git a/vcsserver/lib/_vendor/statsd/__init__.py b/vcsserver/lib/_vendor/statsd/__init__.py
--- a/vcsserver/lib/_vendor/statsd/__init__.py
+++ b/vcsserver/lib/_vendor/statsd/__init__.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, division, unicode_literals
+
 
 import logging
 
diff --git a/vcsserver/lib/_vendor/statsd/base.py b/vcsserver/lib/_vendor/statsd/base.py
--- a/vcsserver/lib/_vendor/statsd/base.py
+++ b/vcsserver/lib/_vendor/statsd/base.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, division, unicode_literals
+
 
 import re
 import random
diff --git a/vcsserver/lib/_vendor/statsd/stream.py b/vcsserver/lib/_vendor/statsd/stream.py
--- a/vcsserver/lib/_vendor/statsd/stream.py
+++ b/vcsserver/lib/_vendor/statsd/stream.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, division, unicode_literals
+
 
 import socket
 
diff --git a/vcsserver/lib/_vendor/statsd/timer.py b/vcsserver/lib/_vendor/statsd/timer.py
--- a/vcsserver/lib/_vendor/statsd/timer.py
+++ b/vcsserver/lib/_vendor/statsd/timer.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, division, unicode_literals
+
 
 import functools
 
diff --git a/vcsserver/lib/_vendor/statsd/udp.py b/vcsserver/lib/_vendor/statsd/udp.py
--- a/vcsserver/lib/_vendor/statsd/udp.py
+++ b/vcsserver/lib/_vendor/statsd/udp.py
@@ -1,4 +1,4 @@
-from __future__ import absolute_import, division, unicode_literals
+
 
 import socket
 
diff --git a/vcsserver/lib/rc_cache/backends.py b/vcsserver/lib/rc_cache/backends.py
--- a/vcsserver/lib/rc_cache/backends.py
+++ b/vcsserver/lib/rc_cache/backends.py
@@ -265,7 +265,7 @@ class BaseRedisBackend(redis_backend.Red
 
     def get_mutex(self, key):
         if self.distributed_lock:
-            lock_key = u'_lock_{0}'.format(safe_unicode(key))
+            lock_key = '_lock_{0}'.format(safe_unicode(key))
             return get_mutex_lock(self.client, lock_key, self._lock_timeout,
                                   auto_renewal=self._lock_auto_renewal)
         else:
diff --git a/vcsserver/lib/rc_cache/utils.py b/vcsserver/lib/rc_cache/utils.py
--- a/vcsserver/lib/rc_cache/utils.py
+++ b/vcsserver/lib/rc_cache/utils.py
@@ -105,11 +105,11 @@ class RhodeCodeCacheRegion(CacheRegion):
         def get_or_create_for_user_func(key_generator, user_func, *arg, **kw):
 
             if not condition:
-                log.debug('Calling un-cached method:%s', user_func.func_name)
+                log.debug('Calling un-cached method:%s', user_func.__name__)
                 start = time.time()
                 result = user_func(*arg, **kw)
                 total = time.time() - start
-                log.debug('un-cached method:%s took %.4fs', user_func.func_name, total)
+                log.debug('un-cached method:%s took %.4fs', user_func.__name__, total)
                 return result
 
             key = key_generator(*arg, **kw)
@@ -117,7 +117,7 @@ class RhodeCodeCacheRegion(CacheRegion):
             timeout = expiration_time() if expiration_time_is_callable \
                 else expiration_time
 
-            log.debug('Calling cached method:`%s`', user_func.func_name)
+            log.debug('Calling cached method:`%s`', user_func.__name__)
             return self.get_or_create(key, user_func, timeout, should_cache_fn, (arg, kw))
 
         def cache_decorator(user_func):
diff --git a/vcsserver/scm_app.py b/vcsserver/scm_app.py
--- a/vcsserver/scm_app.py
+++ b/vcsserver/scm_app.py
@@ -81,7 +81,7 @@ class HgWeb(mercurial.hgweb.hgweb_mod.hg
         first_chunk = None
 
         try:
-            data = gen.next()
+            data = next(gen)
 
             def first_chunk():
                 yield data
diff --git a/vcsserver/subprocessio.py b/vcsserver/subprocessio.py
--- a/vcsserver/subprocessio.py
+++ b/vcsserver/subprocessio.py
@@ -47,7 +47,7 @@ class StreamFeeder(Thread):
         if type(source) in (type(''), bytes, bytearray):  # string-like
             self.bytes = bytes(source)
         else:  # can be either file pointer or file-like
-            if type(source) in (int, long):  # file pointer it is
+            if type(source) in (int, int):  # file pointer it is
                 # converting file descriptor (int) stdin into file-like
                 try:
                     source = os.fdopen(source, 'rb', 16384)
@@ -189,7 +189,7 @@ class BufferedGenerator(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         while not len(self.data) and not self.worker.EOF.is_set():
             self.worker.data_added.clear()
             self.worker.data_added.wait(0.2)
@@ -440,7 +440,7 @@ class SubprocessIOChunker(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         # Note: mikhail: We need to be sure that we are checking the return
         # code after the stdout stream is closed. Some processes, e.g. git
         # are doing some magic in between closing stdout and terminating the
@@ -449,7 +449,7 @@ class SubprocessIOChunker(object):
         result = None
         stop_iteration = None
         try:
-            result = self.output.next()
+            result = next(self.output)
         except StopIteration as e:
             stop_iteration = e
 
diff --git a/vcsserver/tests/conftest.py b/vcsserver/tests/conftest.py
--- a/vcsserver/tests/conftest.py
+++ b/vcsserver/tests/conftest.py
@@ -39,7 +39,7 @@ def repeat(request):
 @pytest.fixture(scope='session')
 def vcsserver_port(request):
     port = get_available_port()
-    print('Using vcsserver port %s' % (port, ))
+    print(('Using vcsserver port %s' % (port, )))
     return port
 
 
diff --git a/vcsserver/tests/test_git.py b/vcsserver/tests/test_git.py
--- a/vcsserver/tests/test_git.py
+++ b/vcsserver/tests/test_git.py
@@ -113,7 +113,7 @@ class TestReraiseSafeExceptions(object):
         methods = inspect.getmembers(git_remote, predicate=inspect.ismethod)
         for method_name, method in methods:
             if not method_name.startswith('_') and method_name not in ['vcsserver_invalidate_cache']:
-                assert method.im_func.__code__ == decorator.__code__
+                assert method.__func__.__code__ == decorator.__code__
 
     @pytest.mark.parametrize('side_effect, expected_type', [
         (dulwich.errors.ChecksumMismatch('0000000', 'deadbeef'), 'lookup'),
diff --git a/vcsserver/tests/test_hg.py b/vcsserver/tests/test_hg.py
--- a/vcsserver/tests/test_hg.py
+++ b/vcsserver/tests/test_hg.py
@@ -52,7 +52,7 @@ class TestReraiseSafeExceptions(object):
         decorator = hg.reraise_safe_exceptions(None)
         for method_name, method in methods:
             if not method_name.startswith('_') and method_name not in ['vcsserver_invalidate_cache']:
-                assert method.im_func.__code__ == decorator.__code__
+                assert method.__func__.__code__ == decorator.__code__
 
     @pytest.mark.parametrize('side_effect, expected_type', [
         (hgcompat.Abort(), 'abort'),
diff --git a/vcsserver/tests/test_hgpatches.py b/vcsserver/tests/test_hgpatches.py
--- a/vcsserver/tests/test_hgpatches.py
+++ b/vcsserver/tests/test_hgpatches.py
@@ -28,7 +28,7 @@ def test_patch_largefiles_capabilities_a
         patched_capabilities):
     lfproto = hgcompat.largefiles.proto
     hgpatches.patch_largefiles_capabilities()
-    assert lfproto._capabilities.func_name == '_dynamic_capabilities'
+    assert lfproto._capabilities.__name__ == '_dynamic_capabilities'
 
 
 def test_dynamic_capabilities_uses_original_function_if_not_enabled(
diff --git a/vcsserver/tests/test_subprocessio.py b/vcsserver/tests/test_subprocessio.py
--- a/vcsserver/tests/test_subprocessio.py
+++ b/vcsserver/tests/test_subprocessio.py
@@ -100,7 +100,7 @@ def test_does_not_fail_on_stderr(environ
 
 @pytest.mark.parametrize('size', [1, 10 ** 5])
 def test_output_with_no_input(size, environ):
-    print(type(environ))
+    print((type(environ)))
     data = 'X'
     args = _get_python_args('sys.stdout.write("%s" * %d)' % (data, size))
     output = ''.join(subprocessio.SubprocessIOChunker(args, shell=False, env=environ))
@@ -118,7 +118,7 @@ def test_output_with_no_input_does_not_f
         )
     )
 
-    print("{} {}".format(len(data * size), len(output)))
+    print(("{} {}".format(len(data * size), len(output))))
     assert output == data * size