In theory at least no real compatibility breaking changes should happen within the same major release, but exceptions can of course exist. Still, if any such they should be very very rare. In essence it should always be safe to move forward within the same major release version(major.minor.patch/fix).
If there are exceptional compatibility breaking features or changes they should be documented in the release notes so look at those.
https://github.com/godotengine/godot/blob/3.3/CHANGELOG.md#33---2021-04-21
Just to be sure tho, I'll tag @Calinou so they can correct me on anything I might be wrong about here.