diff --git a/HISTORY.md b/HISTORY.md
index a098131..d567753 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -3,6 +3,12 @@
 https://github.com/josdejong/jsoneditor
 
 
+## not yet published, version 9.0.1
+
+- Fixed broken link to the Ace editor website (https://ace.c9.io/).
+  Thanks @p3x-robot.
+
+
 ## 2020-05-24, version 9.0.0
 
 - Implemented option `limitDragging`, see #962. This is a breaking change when 
diff --git a/docs/api.md b/docs/api.md
index 188a4c2..085bb3c 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -767,7 +767,7 @@ See also `JSONEditor.update(json)`.
 
 #### `JSONEditor.setMode(mode)`
 
-Switch mode. Mode `code` requires the [Ace editor](http://ace.ajax.org/).
+Switch mode. Mode `code` requires the [Ace editor](https://ace.c9.io/).
 
 *Parameters:*