What are the official supported file system in Ubuntu 16.04 and above

we have been doing interop QA for Ubuntu with SAN configurations. i was trying to get some info on the officially supported client file system’s in Ubuntu server and couldn’t get the same from any specific document. i was looking for the following versions of Ubuntu:
Ubuntu server 16.04 and 18.04

I have already validated this Ext4 and XFS. But need a confirmation if there are other file system which is officially supported by them.