diff --git a/segment/analytics/client.py b/segment/analytics/client.py
index 1d4e35d..0f8015c 100644
--- a/segment/analytics/client.py
+++ b/segment/analytics/client.py
@@ -267,7 +267,7 @@ def _enqueue(self, msg):
         """Push a new `msg` onto the queue, return `(success, msg)`"""
         timestamp = msg['timestamp']
         if timestamp is None:
-            timestamp = datetime.utcnow().replace(tzinfo=tzutc())
+            timestamp = datetime.now(tz=tzutc())
         message_id = msg.get('messageId')
         if message_id is None:
             message_id = uuid4()
diff --git a/segment/analytics/request.py b/segment/analytics/request.py
index 273247c..1f5a56e 100644
--- a/segment/analytics/request.py
+++ b/segment/analytics/request.py
@@ -18,7 +18,7 @@ def post(write_key, host=None, gzip=False, timeout=15, proxies=None, oauth_manag
     log = logging.getLogger('segment')
     body = kwargs
     if not "sentAt" in body.keys():
-        body["sentAt"] = datetime.utcnow().replace(tzinfo=tzutc()).isoformat()
+        body["sentAt"] = datetime.now(tz=tzutc()).isoformat()
     body["writeKey"] = write_key
     url = remove_trailing_slash(host or 'https://api.segment.io') + '/v1/batch'
     auth = None