Merge remote-tracking branch 'origin/6.1' into 7.x

Author: kingjia90

doc/00_Installation.md

@@ -34,7 +34,10 @@ return [
 bin/console pimcore:bundle:install AdvancedObjectSearchBundle
 ```
 
+**Warning:**
+Before proceeding, please make sure your classes are not using any object data type named as `checksum` as this is currently a reserved field name for the search index.
+
 ## Required Backend User Permission
 To access the Advanced Object Search feature, a user needs to meet at least one of the following criteria:
 * Be an `admin` user.
-* Have `bundle_advancedsearch_search` permission.
+* Have `bundle_advancedsearch_search` permission.