diff --git a/Database/Persist/MongoDB.hs b/Database/Persist/MongoDB.hs
--- a/Database/Persist/MongoDB.hs
+++ b/Database/Persist/MongoDB.hs
@@ -481,6 +481,8 @@
         i2bs l i = BS.unfoldr (\l' -> if l' < 0 then Nothing else Just (fromIntegral (i `shiftR` l'), l' - 8)) (l-8)
         {-# INLINE i2bs #-}
 
+-- | older versions versions of haddock (like that on hackage) do not show that this defines
+-- @BackendKey DB.MongoContext = MongoKey { unMongoKey :: DB.ObjectId }@
 instance PersistStore DB.MongoContext where
     newtype BackendKey DB.MongoContext = MongoKey { unMongoKey :: DB.ObjectId }
         deriving (Show, Read, Eq, Ord, PersistField)
diff --git a/persistent-mongoDB.cabal b/persistent-mongoDB.cabal
--- a/persistent-mongoDB.cabal
+++ b/persistent-mongoDB.cabal
@@ -1,5 +1,5 @@
 name:            persistent-mongoDB
-version:         2.0.0.1
+version:         2.0.0.2
 license:         MIT
 license-file:    LICENSE
 author:          Greg Weber <greg@gregweber.info>