New Prefab lookup on BaseEntity

Hello! I am trying to bring my plugins back up from this newest update, however it looks like my plugins are erroring out when I try to lookup a prefab name. So for example e.LookupShortPrefabName() is causing: CS1061: Type `BaseEntity' does not contain a definition for `LookupShortPrefabName' and no extension method `LookupShortPrefabName' of type `BaseEntity' could be found. Are you missing an assembly reference?

I would normally start looking through the code, but I am not in a position to do so as I only have SSH access to the physical server at the moment. Does anyone know what this has been changed to?