diff --git a/ietf/api/__init__.py b/ietf/api/__init__.py
index b4c6203d985..54b4b7424b3 100644
--- a/ietf/api/__init__.py
+++ b/ietf/api/__init__.py
@@ -12,12 +12,11 @@
 
 import debug                            # pyflakes:ignore
 
-import tastypie
 import tastypie.resources
+import tastypie.serializers
 from tastypie.api import Api
 from tastypie.bundle import Bundle
 from tastypie.exceptions import ApiFieldError
-from tastypie.serializers import Serializer # pyflakes:ignore (we're re-exporting this)
 from tastypie.fields import ApiField
 
 _api_list = []
@@ -152,3 +151,8 @@ def dehydrate(self, bundle, for_list=True):
             dehydrated = self.dehydrate_related(fk_bundle, fk_resource, for_list=for_list)
             fk_resource._meta.cache.set(cache_key, dehydrated)
         return dehydrated
+
+
+class Serializer(tastypie.serializers.Serializer):
+    def format_datetime(self, data):
+        return data.astimezone(datetime.timezone.utc).replace(tzinfo=None).isoformat(timespec="seconds") + "Z"