Thanks. LZDoom always supported GL3 and GL4 besides GL2 with a few missing GZDoom features, anyway it's an older renderer. I know i said i was going to drop GL2 and XP but some bad things happened. In short i suffered anaemia and depression and i continued backporting fixes (that was easy) then there were serious bugs and while i was at it recently i backported more stuff (and there were some incomplete things here and there). Besides the pandemic continued and there's the hardware shortage. Also i don't like leaving things buggy/unfinished. LZDoom is not fully compatible but TrailBlazer right now works with the latest devbuild. Actually i rarely play mods anymore, just check if they run sometimes.
Now on ZDoom32 i did some cleanup but in the end i've added a proper new UM skill level with the double spawn thing (now it can be hidden with menu_hideextreme). I've also backckported compat_oldrandom (and it's clean in ZDoom since it's pre-ZScript). I've also ported other recent compat options for closer vanilla compatibility and they are active in the Doom modes too (they should work but i haven't done much testing). It has some more fixes too but i don't remember what they fixed.
I've marked the release as pre-release for now so it doesn't appear as the latest.
https://github.com/drfrag666/gzdoom/releases/tag/2.8.6