diff --git a/Database/Persist/MongoDB.hs b/Database/Persist/MongoDB.hs
--- a/Database/Persist/MongoDB.hs
+++ b/Database/Persist/MongoDB.hs
@@ -487,12 +487,6 @@
     newtype BackendKey DB.MongoContext = MongoKey { unMongoKey :: DB.ObjectId }
         deriving (Show, Read, Eq, Ord, PersistField)
 
-    backendKeyToValues (MongoKey oid)   = [oidToPersistValue oid]
-    backendKeyFromValues [poid@(PersistObjectId _)] =
-        Right $ MongoKey $ persistObjectIdToDbOid poid
-    backendKeyFromValues s = Left $ "backendKeyFromValues, expected a list with one PersistObjectId, got: "
-        `mappend` (T.pack $ show s)
-
     insert record = DB.insert (collectionName record) (toInsertDoc record)
                 >>= keyFrom_idEx
 
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:         2.0.0.2
+version:         2.0.1
 license:         MIT
 license-file:    LICENSE
 author:          Greg Weber <greg@gregweber.info>
@@ -19,7 +19,7 @@
 
 library
     build-depends:   base               >= 4 && < 5
-                   , persistent         >= 2.0     && < 2.1
+                   , persistent         >= 2.0.1   && < 2.1
                    , text               >= 0.8
                    , transformers       >= 0.2.1
                    , containers         >= 0.2