Versioning policy for usage of Internal modules

I'm maintaining [`pomaps`](http://hackage.haskell.org/package/pomaps), a library that allows maps and sets to be indexed by partial orders. I'm using `Data.Map.{Strict,Lazy}` in the internal representation and use some functions internal to `containers`, like `balance{L,R}`.

I understand that this means I have to track the development of `containers` more closely, but could there be some kind of versioning policy even for the internal modules? I was thinking of something like "breaking changes in internal modules may happen at any MINOR version bump". This would allow more lax upper bounds like `< 0.5.12` instead of `<= 0.5.11.0`.