Lua is famous for breaking compatibility between versions. And Lua users are quite aware of the situation. But outsiders tend to overblow the situation, making more noise than the people actually having to deal with it.
The Lua creators are very careful and deliberate in how they break compatibility.
One such thing they do is they avoid subtle changes that can lead to incorrect/different results, and prefer hard things that lead to obvious compile time errors.
But most of the time, the changes between minor revisions aren't a big deal. On the Lua side, authors have been pretty good about figuring out how to make their scripts run across all versions because the changes haven't been that big. On the C side, the API changes can be a little more dramatic, but authors have been good about handling the differences.
Most are stuck with Lua 5.1 anyway as it's the version supported by LuaJIT2. But 5.1 is very good. And the Lua community is very loosely connected and quite different due Lua's embedded nature.
I made much Lua code, and one thing that makes a major difference, is that Lua devs frequently discuss what they are planning to break.
For example I wrote many games in Lua 5.1, that actually work in Lua 5 if I wanted to, and also work in Lua 5.2, despite 5.2 not existing when I wrote them.
I don't checked yet the changes on 5.3, but I suspect my games might work on 5.3 without changes too.
The Lua creators are very careful and deliberate in how they break compatibility.
One such thing they do is they avoid subtle changes that can lead to incorrect/different results, and prefer hard things that lead to obvious compile time errors.
But most of the time, the changes between minor revisions aren't a big deal. On the Lua side, authors have been pretty good about figuring out how to make their scripts run across all versions because the changes haven't been that big. On the C side, the API changes can be a little more dramatic, but authors have been good about handling the differences.