diff --git a/modules/format_activity.py b/modules/format_activity.py
index b2fdfc38..ebc770b3 100644
--- a/modules/format_activity.py
+++ b/modules/format_activity.py
@@ -119,7 +119,7 @@ class Module(ModuleManager.BaseModule):
             event["channel"].topic, event["channel"])
 
         unix_dt = datetime.datetime.utcfromtimestamp(event["set_at"])
-        dt = datetime.datetime.strftime(unix_dt, DATETIME_FORMAT)
+        dt = datetime.datetime.strftime(unix_dt, utils.ISO8601_PARSE)
         line = "topic set at %s" % dt
         self._event("topic-timestamp", event["server"], line,
             event["channel"].name)
diff --git a/modules/print_activity.py b/modules/print_activity.py
index fe8f0edf..48b539f5 100644
--- a/modules/print_activity.py
+++ b/modules/print_activity.py
@@ -1,8 +1,6 @@
 import datetime
 from src import EventManager, ModuleManager, utils
 
-DATETIME_FORMAT = "%Y-%m-%dT%H:%M:%SZ"
-
 class Module(ModuleManager.BaseModule):
     def _print_line(self, target, context, line):
         formatted_line = utils.irc.parse_format(line)