diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -2,6 +2,12 @@
 
 ## Unreleased
 
+## 0.4.5.0 (2023-04-09)
+
+### Other Changes
+
+* Support GHC 9.6
+
 ## 0.4.4.0 (2022-12-27)
 
 * Support GHC 9.4
diff --git a/polysemy-plugin.cabal b/polysemy-plugin.cabal
--- a/polysemy-plugin.cabal
+++ b/polysemy-plugin.cabal
@@ -1,11 +1,11 @@
 cabal-version: 2.0
 
--- This file has been generated from package.yaml by hpack version 0.34.7.
+-- This file has been generated from package.yaml by hpack version 0.35.2.
 --
 -- see: https://github.com/sol/hpack
 
 name:           polysemy-plugin
-version:        0.4.4.0
+version:        0.4.5.0
 synopsis:       Disambiguate obvious uses of effects.
 description:    Please see the README on GitHub at <https://github.com/polysemy-research/polysemy/tree/master/polysemy-plugin#readme>
 category:       Polysemy
@@ -27,7 +27,7 @@
 
 custom-setup
   setup-depends:
-      Cabal
+      Cabal <3.11
     , base >=4.9 && <5
     , cabal-doctest >=1.0.6 && <1.1
 
@@ -70,7 +70,7 @@
     , ghc-tcplugins-extra >=0.3 && <0.5
     , polysemy >=1.7
     , syb ==0.7.*
-    , transformers >=0.5.2.0 && <0.6
+    , transformers >=0.5.2.0 && <0.7
   default-language: Haskell2010
 
 test-suite polysemy-plugin-test
@@ -111,17 +111,17 @@
   build-depends:
       base >=4.9 && <5
     , containers >=0.5 && <0.7
-    , doctest >=0.16.0.1 && <0.21
+    , doctest >=0.16.0.1 && <0.22
     , ghc >=8.6.5 && <10
     , ghc-tcplugins-extra >=0.3 && <0.5
     , hspec >=2.6.0 && <3
     , hspec-discover
-    , inspection-testing >=0.4.2 && <0.5
+    , inspection-testing >=0.4.2 && <0.6
     , polysemy >=1.3.0.0
     , polysemy-plugin
     , should-not-typecheck >=2.1.0 && <3
     , syb ==0.7.*
-    , transformers >=0.5.2.0 && <0.6
+    , transformers >=0.5.2.0 && <0.7
+  default-language: Haskell2010
   if flag(corelint)
     ghc-options: -dcore-lint -dsuppress-all
-  default-language: Haskell2010
diff --git a/src/Polysemy/Plugin/Fundep.hs b/src/Polysemy/Plugin/Fundep.hs
--- a/src/Polysemy/Plugin/Fundep.hs
+++ b/src/Polysemy/Plugin/Fundep.hs
@@ -52,6 +52,16 @@
 import           Polysemy.Plugin.Fundep.Unification
 import           Polysemy.Plugin.Fundep.Utils
 
+#if __GLASGOW_HASKELL__ >= 906
+#define SUBST Subst
+#define GET_TYVAR getTyVar_maybe
+import           GHC.Core.TyCo.Subst (SUBST)
+import           GHC.Core.TyCo.Compare (eqType, nonDetCmpType)
+#else
+#define SUBST TCvSubst
+#define GET_TYVAR tcGetTyVar_maybe
+#endif
+
 #if __GLASGOW_HASKELL__ >= 900
 import           GHC.Builtin.Types.Prim (alphaTys)
 import           GHC.Plugins (idType, tyConClass_maybe, ppr, Outputable, sep, text, (<+>), parens, emptyUFM)
@@ -60,7 +70,7 @@
 import           GHC.Tc.Types
 import           GHC.Tc.Types.Constraint
 import           GHC.Tc.Utils.Env (tcGetInstEnvs)
-import           GHC.Tc.Utils.TcType (tcSplitPhiTy, tcSplitTyConApp, tcGetTyVar_maybe, tcSplitAppTy_maybe)
+import           GHC.Tc.Utils.TcType (tcSplitPhiTy, tcSplitTyConApp, GET_TYVAR, tcSplitAppTy_maybe)
 import           GHC.Tc.Solver.Monad hiding (tcLookupClass)
 import           GHC.Core.Class (classTyCon)
 import           GHC.Core.InstEnv (lookupInstEnv, is_dfun)
@@ -80,14 +90,12 @@
 import           TcEvidence
 import           TcPluginM (tcPluginIO)
 import           TcRnTypes
-import           TcType (tcSplitPhiTy, tcSplitTyConApp, tcGetTyVar_maybe, tcSplitAppTy_maybe)
+import           TcType (tcSplitPhiTy, tcSplitTyConApp, GET_TYVAR, tcSplitAppTy_maybe)
 import           TcSMonad hiding (tcLookupClass)
 import           Type
 import           TysPrim (alphaTys)
 #endif
 
-
-
 fundepPlugin :: TcPlugin
 fundepPlugin = TcPlugin
   { tcPluginInit =
@@ -193,12 +201,15 @@
                 True -> pure $ Just eff
                 False -> pure Nothing
 
-
 ------------------------------------------------------------------------------
 -- | @checkExtraEvidence givens subst c@ returns 'True' iff we can prove that
 -- the constraint @c@ holds under the substitution @subst@ in the context of
 -- @givens@.
-checkExtraEvidence :: Set PredType' -> TCvSubst -> PredType -> TcM Bool
+checkExtraEvidence ::
+  Set PredType' ->
+  SUBST ->
+  PredType ->
+  TcM Bool
 checkExtraEvidence givens subst = flip evalStateT givens . getInstance . substTy subst
 
 
@@ -240,8 +251,8 @@
 skolemsForInterpreter :: Type -> Set TyVar
 skolemsForInterpreter ty =
   case tcSplitAppTy_maybe ty of
-    Just (tcGetTyVar_maybe -> Just skolem, _) -> S.singleton skolem
-    _ -> maybe mempty S.singleton $ tcGetTyVar_maybe ty
+    Just (GET_TYVAR -> Just skolem, _) -> S.singleton skolem
+    _ -> maybe mempty S.singleton $ GET_TYVAR ty
 
 
 ------------------------------------------------------------------------------
diff --git a/src/Polysemy/Plugin/Fundep/Unification.hs b/src/Polysemy/Plugin/Fundep/Unification.hs
--- a/src/Polysemy/Plugin/Fundep/Unification.hs
+++ b/src/Polysemy/Plugin/Fundep/Unification.hs
@@ -25,7 +25,15 @@
 import           GhcPlugins (Outputable, ppr, parens, text, (<+>))
 #endif
 
+#if __GLASGOW_HASKELL__ >= 906
+#define SUBST Subst
+import           GHC.Core.TyCo.Subst (SUBST)
+import           GHC.Core.TyCo.Compare (eqType, nonDetCmpType)
+#else
+#define SUBST TCvSubst
+#endif
 
+
 ------------------------------------------------------------------------------
 -- | The context in which we're attempting to solve a constraint.
 data SolveContext
@@ -64,7 +72,7 @@
     :: SolveContext
     -> Type  -- ^ wanted
     -> Type  -- ^ given
-    -> Maybe TCvSubst
+    -> Maybe SUBST
 unify solve_ctx = tryUnifyUnivarsButNotSkolems skolems
   where
     skolems :: Set TyVar
@@ -81,7 +89,7 @@
 #define APART Skolem
 #endif
 
-tryUnifyUnivarsButNotSkolems :: Set TyVar -> Type -> Type -> Maybe TCvSubst
+tryUnifyUnivarsButNotSkolems :: Set TyVar -> Type -> Type -> Maybe SUBST
 tryUnifyUnivarsButNotSkolems skolems goal inst =
   case tcUnifyTysFG
          (bool BINDME APART . flip S.member skolems)