Not entirely. I changed the signatures of IntMap.findMin and findMax to return the key/value pair. Previously they only returned the value. I believe this was a typo -- findMin was defined as "fst . runIdentity . minView" but it "should" have been "fst . runIdentity . minViewWithKey". I say "should" because Map.findMin also returns the pair, and the documentation for the functions made it seem like that's what they should return. But I don't think its a major compatibility issue because these functions are still not published in the Haddock indices (http://www.haskell.org/ghc/docs/latest/html/libraries/containers/Data-IntMap.html <-- no findMin there) so whoever is using them is doing so at the risk of code breakage.

But if this still counts as API change I'd be glad to make another that keeps signatures unchanged. However I do think it is ridiculous for findMin to return only the value and not the key as well.