diff --git a/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_19.rst b/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_19.rst
index 9daafab5bca..d76594ff90c 100644
--- a/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_19.rst
+++ b/developer_manual/app_publishing_maintenance/app_upgrade_guide/upgrade_to_19.rst
@@ -7,6 +7,11 @@ Upgrade to Nextcloud 19
 Front-end changes
 -----------------
 
+Babel Polyfill removal
+^^^^^^^^^^^^^^^^^^^^^^
+
+Nextcloud 19 no longer ships a global Babel Polyfill but uses core-js instead. Make sure your front-end scripts don't reply on polyfilled browser APIs.
+
 jQuery deprecation
 ^^^^^^^^^^^^^^^^^^