The subgroup and ggroup modules have different advantages. Is it possible to use both of them in the same installation?
I created a test site with both enabled, and it seemed like the only thing I could use in the UI was the subgroup module. When I uninstalled that, then the ggroup UI became available.
Trying to add subgroup to a site where I had previously used ggroup failed with fatal errors about a missing plugin, but I wasn't sure if that was related to having already created group types and groups without having had the module installed.
Needs work
1.0
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
ggroup 2.x is incompatible with groups 3, and there's no upgrade path from ggroup 2.x to 3.x. It is probably a bit late now, but I think this change should have been made in a 4.x branch so that the plugin upgrade path could have been decoupled from the groups upgrade path.
Changing the plugin ID in a minor release of 2.x seems quite disruptive here.