diff --git a/overload.cabal b/overload.cabal
--- a/overload.cabal
+++ b/overload.cabal
@@ -1,5 +1,5 @@
 name:                overload
-version:             0.1.0.3
+version:             0.1.0.4
 synopsis:            Finite overloading
 description:         Provides a mechanism for finite overloading
 homepage:            https://gitlab.com/LukaHorvat/overload
@@ -22,7 +22,7 @@
                        Overload.Diff
   build-depends:       base >= 4.7 && < 5
                      , template-haskell
-                     , simple-effects
+                     , simple-effects >= 0.9.0.0
                      , th-expand-syns
   default-language:    Haskell2010
   ghc-options:         -Wall
diff --git a/src/Overload/General.hs b/src/Overload/General.hs
--- a/src/Overload/General.hs
+++ b/src/Overload/General.hs
@@ -10,7 +10,7 @@
 
 type VariableMapping a b = [(a, TypeTree b)]
 
-trySetVar :: (MonadEffectState (VariableMapping a b) m, Eq a, Eq b) => a -> TypeTree b -> m Bool
+trySetVar :: (MonadEffect (State (VariableMapping a b)) m, Eq a, Eq b) => a -> TypeTree b -> m Bool
 trySetVar name typ = do
     mapping <- getState
     case lookup name mapping of
@@ -24,7 +24,7 @@
 isMoreGeneralThan t1 t2 =
     runIdentity (handleStateT ([] :: VariableMapping a b) (isMoreGeneralThan' t1 t2))
 
-isMoreGeneralThan' :: (MonadEffectState (VariableMapping a b) m, Eq a, Eq b)
+isMoreGeneralThan' :: (MonadEffect (State (VariableMapping a b)) m, Eq a, Eq b)
                    => TypeTree a -> TypeTree b -> m Bool
 isMoreGeneralThan' (Var n) t = trySetVar n t
 isMoreGeneralThan' (Concrete n1) (Concrete n2) | n1 == n2 = return True
diff --git a/src/Overload/Normal.hs b/src/Overload/Normal.hs
--- a/src/Overload/Normal.hs
+++ b/src/Overload/Normal.hs
@@ -12,7 +12,7 @@
 
 type FreshSource a = ([(a, Normal)], Normal)
 
-lookupName :: (MonadEffectState (FreshSource a) m, Eq a) => a -> m Normal
+lookupName :: (MonadEffect (State (FreshSource a)) m, Eq a) => a -> m Normal
 lookupName name = do
     (table, Normal top) <- getState
     case lookup name table of
@@ -21,7 +21,7 @@
             return (Normal top)
         Just n  -> return n
 
-freshVar :: forall a m. MonadEffectState (FreshSource a) m => m Normal
+freshVar :: forall a m. MonadEffect (State (FreshSource a)) m => m Normal
 freshVar = do
     (table, Normal top) :: FreshSource a <- getState
     setState (table, Normal (top + 1))