diff --git a/oslo_utils/tests/test_timeutils.py b/oslo_utils/tests/test_timeutils.py
index 0f540f46..3c765a91 100644
--- a/oslo_utils/tests/test_timeutils.py
+++ b/oslo_utils/tests/test_timeutils.py
@@ -66,7 +66,7 @@ class TimeUtilsTest(test_base.BaseTestCase):
 
     @mock.patch('datetime.datetime', wraps=datetime.datetime)
     def _test_is_older_than(self, fn, datetime_mock):
-        datetime_mock.utcnow.return_value = self.skynet_self_aware_time
+        datetime_mock.now.return_value = self.skynet_self_aware_time
         expect_true = timeutils.is_older_than(fn(self.one_minute_before), 59)
         self.assertTrue(expect_true)
         expect_false = timeutils.is_older_than(fn(self.one_minute_before), 60)
@@ -89,7 +89,7 @@ class TimeUtilsTest(test_base.BaseTestCase):
 
     @mock.patch('datetime.datetime', wraps=datetime.datetime)
     def _test_is_newer_than(self, fn, datetime_mock):
-        datetime_mock.utcnow.return_value = self.skynet_self_aware_time
+        datetime_mock.now.return_value = self.skynet_self_aware_time
         expect_true = timeutils.is_newer_than(fn(self.one_minute_after),
                                               59)
         self.assertTrue(expect_true)
@@ -202,7 +202,7 @@ class TimeUtilsTest(test_base.BaseTestCase):
         self.assertTrue(timeutils.is_soon(expires, 600))
 
         with mock.patch('datetime.datetime') as datetime_mock:
-            datetime_mock.utcnow.return_value = self.skynet_self_aware_time
+            datetime_mock.now.return_value = self.skynet_self_aware_time
             expires = timeutils.utcnow()
             self.assertTrue(timeutils.is_soon(expires, 0))
 
diff --git a/oslo_utils/timeutils.py b/oslo_utils/timeutils.py
index 23314d28..19c326a1 100644
--- a/oslo_utils/timeutils.py
+++ b/oslo_utils/timeutils.py
@@ -137,7 +137,7 @@ def utcnow(with_timezone=False):
             return utcnow.override_time
     if with_timezone:
         return datetime.datetime.now(tz=iso8601.iso8601.UTC)
-    return datetime.datetime.utcnow()
+    return datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
 
 
 utcnow.override_time = None
@@ -153,7 +153,9 @@ def set_time_override(override_time=None):
     :param override_time: datetime instance or list thereof. If not
                           given, defaults to the current UTC time.
     """
-    utcnow.override_time = override_time or datetime.datetime.utcnow()
+    utcnow.override_time = (
+        override_time or
+        datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None))
 
 
 def advance_time_delta(timedelta):