If any entity was removed, or the types of any entities or the definitions of datatypes or classes were changed, or orphan instances were added or any instances were removed, then the new A.B must be greater than the previous A.B. Note that modifying imports or depending on a newer version of another package may cause extra orphan instances to be exported and thus force a major version change.```
per [Haskell's Package Version Policy](http://www.haskell.org/haskellwiki/Package_versioning_policy).