We all knew it had to happen at some point. As of right now, TAB has 40 Bukkit modules for different MC versions, lots of which are not being used by anyone anymore. Starting with 1.20.5, paper decided to make a harder fork from spigot, removing CraftBukkit relocation, requiring 2 implementations for each version - 1 for Spigot and 1 for Paper. All of this causes the plugin to take forever to compile and officially supporting versions that weren't tested for years isn't ideal either.
Eventually, I have decided to start dropping support for older MC versions on Bukkit. When and which versions is still not fully planned, but you can check the estimations below.
Players with unsupported MC versions will remain supported (either on a proxy or through ViaVersion), but plugin will no longer start on those Bukkit versions.
When MC version 26.1 comes out, TAB 6.0.0 will be released, dropping support for non-latest minor versions of