Lua 5.1 to 5.2 was a fairly significant breaking change; one that has forked the community to this day with luaJIT never coming on board. 5.2 to 5.3 also broke things with the introduction of integers but mostly at the level of bindings. There is also very little included in terms of standard library and while luarocks exists many significant packages go abandoned. There are breaking language changes in the upcoming…
NeoVim is committing to 5.1 and leaving it at that.