diff --git a/.upgrade.yml b/.upgrade.yml
index 581698386..09719e927 100644
--- a/.upgrade.yml
+++ b/.upgrade.yml
@@ -165,7 +165,6 @@ mappings:
   GroupImportForm: SilverStripe\Admin\GroupImportForm
   LeftAndMain: SilverStripe\Admin\LeftAndMain
   LeftAndMain_HTTPResponse: SilverStripe\Admin\LeftAndMain_HTTPResponse
-  LeftAndMain_TreeNode: SilverStripe\Admin\LeftAndMain_TreeNode
   LeftAndMain_SearchFilter: SilverStripe\Admin\LeftAndMain_SearchFilter
   LeftAndMainExtension: SilverStripe\Admin\LeftAndMainExtension
   MemberImportForm: SilverStripe\Admin\MemberImportForm
diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index 09e3343ae..c47e156a9 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -1091,6 +1091,14 @@ now generally safer to use the default inherited config, where in the past you w
     If left unset, this will raise an error.
   * `getBackURL` and `getReturnReferer` have been added to safely inspect the current request
     to see if there is a url to redirect back to.
+* `LeftAndMain` class has had all tree manipulation code moved into CMS module class `CMSMain`.
+  This includes:
+  * `LeftAndMain_TreeNode` class -> renamed to `CMSMain_TreeNode`
+  * `SiteTreeAsUL` removed (override left in `CMSMain`)
+  * `getSiteTreeFor()` -> moved to `CMSMain`
+  * `getsubtree()` -> moved to `CMSMain`
+  * `updatetreenodes()` -> moved to `CMSMain`
+  * `savetreenodes()` -> moved to `CMSMain`
   
 
 #### <a name="overview-general-removed"></a>General and Core Removed API