diff --git a/hw-aeson.cabal b/hw-aeson.cabal
--- a/hw-aeson.cabal
+++ b/hw-aeson.cabal
@@ -1,7 +1,7 @@
 cabal-version: 2.2
 
 name:                   hw-aeson
-version:                0.1.4.0
+version:                0.1.5.0
 synopsis:               Convenience functions for Aeson
 description:            Convenience functions for Aeson.
 category:               Data, JSON
@@ -22,9 +22,10 @@
 
 common base                       { build-depends: base                       >= 4.11       && < 5      }
 
+common aeson                      { build-depends: aeson                      >= 1.4        && < 2.1    }
+common containers                 { build-depends: containers                 >= 0.6        && < 0.7   }
 common doctest                    { build-depends: doctest                    >= 0.16.2     && < 0.21   }
 common doctest-discover           { build-depends: doctest-discover           >= 0.2        && < 0.3    }
-common aeson                      { build-depends: aeson                      >= 1.4        && < 2.1    }
 common hedgehog                   { build-depends: hedgehog                   >= 0.6        && < 1.3    }
 common hspec                      { build-depends: hspec                      >= 2.4        && < 3      }
 common text                       { build-depends: text                       >= 1.2        && < 1.3    }
@@ -39,6 +40,7 @@
 library
   import:               base, config
                       , aeson
+                      , containers
                       , text
                       , text-short
                       , unordered-containers
diff --git a/src/HaskellWorks/Data/Aeson/Compat/Map.hs b/src/HaskellWorks/Data/Aeson/Compat/Map.hs
--- a/src/HaskellWorks/Data/Aeson/Compat/Map.hs
+++ b/src/HaskellWorks/Data/Aeson/Compat/Map.hs
@@ -2,18 +2,30 @@
 
 module HaskellWorks.Data.Aeson.Compat.Map
   ( module JM
+  , KeyMap(..)
+  , foldlWithKey'
   ) where
 
+import qualified Data.Map as M
+import qualified HaskellWorks.Data.Aeson.Compat as J
+
 import Data.Text (Text)
 
 #if MIN_VERSION_aeson(2,0,0)
 import Data.Aeson.KeyMap as JM
 #else
-import Data.HashMap.Strict as JM
+import qualified Data.HashMap.Strict as JM
+import Data.HashMap.Strict hiding (foldlWithKey')
 #endif
 
+#if !MIN_VERSION_aeson(2,0,0)
+type KeyMap v = JM.HashMap Text v
+#endif
+
+foldlWithKey' :: (a -> J.Key -> b -> a) -> a -> KeyMap b -> a
 #if MIN_VERSION_aeson(2,0,0)
-type Map v = JM.KeyMap v
+foldlWithKey' f a = M.foldlWithKey' f a . JM.toMap
 #else
-type Map v = JM.HashMap Text v
+foldlWithKey'= JM.foldlWithKey'
 #endif
+