diff --git a/README.md b/README.md
index 6dd3eaf..29fe7e0 100644
--- a/README.md
+++ b/README.md
@@ -11,3 +11,5 @@ Known issues:
 * Disabled users from RT can not be accessed by API, thus will lack email
   address and will fail to be created. Enable all users prior to the migration.
 * Timestamps are not preserved. The Zammad API doesn't seem to allow this.
+* Zammad will send notification for all actions, you probably want to disable
+  outgoing mail for time of import.