diff --git a/bots/zephyr_mirror_backend.py b/bots/zephyr_mirror_backend.py
index 386e078..6ee08b2 100755
--- a/bots/zephyr_mirror_backend.py
+++ b/bots/zephyr_mirror_backend.py
@@ -38,6 +38,7 @@ import optparse
 import os
 import datetime
 import textwrap
+import time
 import signal
 import logging
 import hashlib
@@ -762,8 +763,8 @@ def maybe_forward_to_zephyr(message):
             # Don't try forward private messages with non-MIT users
             # to MIT Zephyr.
             return
-        timestamp_now = datetime.datetime.now().strftime("%s")
-        if float(message["timestamp"]) < float(timestamp_now) - 15:
+        timestamp_now = int(time.time())
+        if float(message["timestamp"]) < timestamp_now - 15:
             logger.warning("Skipping out of order message: %s < %s" %
                            (message["timestamp"], timestamp_now))
             return