Q: Will this be ported or backported to x version?
A: We don't have plans for this. If you want a similar experience for 1.16.5+ versions, you can check out Enhanced Celestials and one of the several meteor mods released for those versions. For 1.7.10, Random Things has a Blood Moon event available and there is the original Falling Meteors.
Q: Is this compatible with existing worlds that previously had Nyx? Will anything that originally depended on Nyx break? What about mod compatibility?
A: Hyxcate still uses the `nyx` mod id and we use DataFixers to take care of any other ids that have changed, any worlds that had Nyx should still work but you won't be able to switch back. Classes were changed around to have unique names which will break compatibility with any mods looking for the old classes. Existing resource packs should remain (mostly) compatible, you can see our Mod Compatibility page regarding known conflicts and solutions.
Q: Does this work with OptiFine? What about shaders?
A: It has been confirmed from our testing that the ambient lighting from our mod's events does in fact work with OptiFine. It also works with certain shaders!
Q: Is this related to the other previously released Nyx forks?
A: We are not associated with those forks or any modpacks or groups that they are connected to. Hyxcate started off as a Nyx fork meant for the Hexxit II modpack before it was rebranded as its own standalone mod.