diff --git a/oauth2_provider/migrations/0006_auto_20171214_2232.py b/oauth2_provider/migrations/0006_auto_20171214_2232.py
index 2b9568f5c..7fb773bf5 100644
--- a/oauth2_provider/migrations/0006_auto_20171214_2232.py
+++ b/oauth2_provider/migrations/0006_auto_20171214_2232.py
@@ -21,7 +21,7 @@ class Migration(migrations.Migration):
         migrations.AddField(
             model_name="refreshtoken",
             name="revoked",
-            field=models.DateTimeField(null=True, default=django.utils.timezone.now),
+            field=models.DateTimeField(null=True, default=None),
             preserve_default=False,
         ),
         migrations.AlterField(