diff --git a/en/04_Changelogs/5.2.0.md b/en/04_Changelogs/5.2.0.md
index c2b0eff56..fddb9a83a 100644
--- a/en/04_Changelogs/5.2.0.md
+++ b/en/04_Changelogs/5.2.0.md
@@ -211,6 +211,12 @@ The following legacy subclasses of [`PasswordEncryptor`](api:SilverStripe\Securi
 - [`PasswordEncryptor_MySQLOldPassword`](api:SilverStripe\Security\PasswordEncryptor_MySQLOldPassword)
 - [`PasswordEncryptor_MySQLPassword`](api:SilverStripe\Security\PasswordEncryptor_MySQLPassword)
 
+The following unused API have been deprecated and will be removed in a future major release:
+
+- Configuration property [`DataObject.subclass_access`](api:SilverStripe\ORM\DataObject->subclass_access)
+- Public static method [`DataObject::disable_subclass_access()`](api:SilverStripe\ORM\DataObject::disable_subclass_access())
+- Public static method [`DataObject::enable_subclass_access()`](api:SilverStripe\ORM\DataObject::enable_subclass_access())
+
 ### `silverstripe/cms` {#api-silverstripe-cms}
 
 The [`SiteTree.hide_ancestor`](api:SilverStripe\CMS\Model\SiteTree->hide_ancestor) configuration property has been deprecated. Use [`SiteTree.hide_pagetypes`](api:SilverStripe\CMS\Model\SiteTree->hide_pagetypes) instead.