Following on from https://bugzilla.redhat.com/show_bug.cgi?id=1000861#c1 we should flip the default for the deprecated "implicit job sharing" to false, with a suitable release note warning people, so that in a future release we can remove the switch entirely.
We are going to need to turn off the "implicit job sharing" before we allow inverted groups (bug 1220610) otherwise as soon as any inverted group is created, every Beaker user will have access to modify any job.
http://gerrit.beaker-project.org/4510
This bug fix is included in beaker-server-22.0-0.git.110.c41cd4c which is currently available for testing here: https://beaker-devel.app.eng.bos.redhat.com/
Beaker 22.0 has been released.