diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index c5a5421e35c..3c576712155 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -13,7 +13,7 @@ This serves two purposes:
 - Add experimental InMemoryPage::getOutputPath overload support
 
 ### Changed
-- for changes in existing functionality.
+- Changed how the documentation search is generated, to be an InMemoryPage instead of a post-build task.
 
 ### Deprecated
 - \Hyde\Framework\Actions\PostBuildTasks\GenerateSearch
@@ -30,3 +30,9 @@ This serves two purposes:
 ### Upgrade Guide
 
 If there are any breaking changes, include an upgrade guide here.
+
+#### Documentation search changes
+
+The documentation search page and search index have been changed to be generated as InMemoryPages instead of a post-build task.
+
+In case you have customized the GenerateSearch post-build task, you will need to adapt your code to the new InMemoryPage, which is generated in the HydeCoreExtension class.