diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 6fd732a6705..5b9369011b4 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -61,6 +61,9 @@ information provided here is intended especially for developers.
   new class boxnet_client(). Note that the method names and return values have changed.
 * Settings pages are now possible for Calendar type plugins. Calendar type plugins that require a settings page to
   work properly will need to set their requires version to a number that is equal to or grater than the 2.6.1 release version.
+* The admin/tool/generator tool was overhauled to use testing data generators and the previous interface to create
+  test data was removed (it was not working correctly anyway). If you were using this tool you will probably need to
+  update your code.
 
 DEPRECATIONS:
 Various previously deprecated functions have now been altered to throw DEBUG_DEVELOPER debugging notices