diff --git a/Database/Persist/MongoDB.hs b/Database/Persist/MongoDB.hs
--- a/Database/Persist/MongoDB.hs
+++ b/Database/Persist/MongoDB.hs
@@ -56,7 +56,7 @@
     , oidToKey
     , recordTypeFromKey
     , readMayObjectId
-    , readMayKey
+    , readMayMongoKey
     , keyToText
 
     -- * PersistField conversion
@@ -209,7 +209,7 @@
 -- | ToPathPiece is used to convert a key to/from text
 instance PathPiece (BackendKey DB.MongoContext) where
     toPathPiece = keyToText
-    fromPathPiece keyText = readMayKey $
+    fromPathPiece keyText = readMayMongoKey $
         -- handle a JSON type prefix
         -- 'o' is a non-hex character, so no confusion here
         case T.uncons keyText of
@@ -220,8 +220,8 @@
 keyToText = T.pack . show . unMongoKey
 
 -- | Convert a Text to a Key
-readMayKey :: Text -> Maybe (BackendKey DB.MongoContext)
-readMayKey = fmap MongoKey . readMayObjectId
+readMayMongoKey :: Text -> Maybe (BackendKey DB.MongoContext)
+readMayMongoKey = fmap MongoKey . readMayObjectId
 
 readMayObjectId :: Text -> Maybe DB.ObjectId
 readMayObjectId str =
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:         2.0.9
+version:         2.1
 license:         MIT
 license-file:    LICENSE
 author:          Greg Weber <greg@gregweber.info>
@@ -19,7 +19,7 @@
 
 library
     build-depends:   base               >= 4 && < 5
-                   , persistent         >= 2.0.8 && < 2.1
+                   , persistent         >= 2.1      && < 3
                    , text               >= 0.8
                    , transformers       >= 0.2.1
                    , containers         >= 0.2