This patch: https://review.gluster.org/12363 removes the following options,
Current worry is that if a volume has these options enabled, we would post-upgrading the server fail for client mounts (or even in other places). Also, removing these options post-upgrade may fail, as the options are not available, and hence may need editing the vol files.
We need to test and ensure that the above occurs, and if it does, we need to fix the situation in consultation with the glusterd team.
Current thoughts for fixing this up is to add these options back but as No-Ops, such that post upgrade functionality is removed, but the presence of the option itself does not cause failures.
We haven't had any complaints/issues for ~2 years around this volume options during upgrade. Moreover the dependent bug reported on v4.0 is no longer supported and was closed long back.
Thus closing this bug report on mainline version.