diff --git a/boltons/funcutils.py b/boltons/funcutils.py
index d11593a..3cd2b1b 100644
--- a/boltons/funcutils.py
+++ b/boltons/funcutils.py
@@ -932,7 +932,7 @@ class FunctionBuilder:
             try:
                 self.kwonlyargs.remove(arg_name)
             except (AttributeError, ValueError):
-                # py2, or py3 and missing from both
+                # missing from both
                 exc = MissingArgument('arg %r not found in %s argument list:'
                                       ' %r' % (arg_name, self.name, args))
                 exc.arg_name = arg_name
diff --git a/boltons/iterutils.py b/boltons/iterutils.py
index 98f4309..fb3d366 100644
--- a/boltons/iterutils.py
+++ b/boltons/iterutils.py
@@ -1398,10 +1398,7 @@ class GUIDerator:
         self.salt = '-'.join([str(self.pid),
                               socket.gethostname() or '<nohostname>',
                               str(time.time()),
-                              codecs.encode(os.urandom(6),
-                                            'hex_codec').decode('ascii')])
-        # that codecs trick is the best/only way to get a bytes to
-        # hexbytes in py2/3
+                              os.urandom(6).hex()])
         return
 
     def __iter__(self):
diff --git a/boltons/statsutils.py b/boltons/statsutils.py
index a2d726c..36a8223 100644
--- a/boltons/statsutils.py
+++ b/boltons/statsutils.py
@@ -128,6 +128,7 @@ system instrumentation package.
 
 import bisect
 from math import floor, ceil
+from collections import Counter
 
 
 class _StatsProperty:
@@ -595,12 +596,7 @@ class Stats:
         bins = sorted(set(bins))
 
         idxs = [bisect.bisect(bins, d) - 1 for d in self.data]
-        count_map = {}  # would have used Counter, but py26 support
-        for idx in idxs:
-            try:
-                count_map[idx] += 1
-            except KeyError:
-                count_map[idx] = 1
+        count_map = Counter(idxs)
 
         bin_counts = [(b, count_map.get(i, 0)) for i, b in enumerate(bins)]
 
diff --git a/docs/timeutils.rst b/docs/timeutils.rst
index 090c28c..1eb8e41 100644
--- a/docs/timeutils.rst
+++ b/docs/timeutils.rst
@@ -28,11 +28,18 @@ working with them:
 
 .. _UTC: https://en.wikipedia.org/wiki/Coordinated_Universal_Time
 
+.. note::
+
+    These days, Python has a `built-in UTC`_, and the UTC tzinfo here, 
+    while equivalent, is just for backwards compat.
+
 .. autoattribute:: boltons.timeutils.UTC
 .. autodata:: boltons.timeutils.LocalTZ
 
 .. autoclass:: boltons.timeutils.ConstantTZInfo
 
+.. _built-in UTC: https://docs.python.org/3/library/datetime.html#datetime.timezone.utc
+
 US timezones
 ------------
 
diff --git a/tests/test_fileutils.py b/tests/test_fileutils.py
index b7c6d61..6d61c13 100644
--- a/tests/test_fileutils.py
+++ b/tests/test_fileutils.py
@@ -14,6 +14,6 @@ def test_fileperms():
 
     assert repr(up) == "FilePerms(user='rwx', group='rwx', other='')"
     assert up.user == 'rwx'
-    assert oct(int(up)).endswith('770')  # 0770 on py2 and 0o770 on py3
+    assert oct(int(up)) == '0o770'
 
     assert int(FilePerms()) == 0