diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog for the [`ghc-typelits-extra`](http://hackage.haskell.org/package/ghc-typelits-extra) package
 
+# 0.2.5 *May 9th 2018*
+* Add support for ghc-typelits-natnormalise-0.6
+
 # 0.2.4 *January 4th 2018*
 * Add support for GHC-8.4.1-alpha1
 
diff --git a/ghc-typelits-extra.cabal b/ghc-typelits-extra.cabal
--- a/ghc-typelits-extra.cabal
+++ b/ghc-typelits-extra.cabal
@@ -1,5 +1,5 @@
 name:                ghc-typelits-extra
-version:             0.2.4
+version:             0.2.5
 synopsis:            Additional type-level operations on GHC.TypeLits.Nat
 description:
   Additional type-level operations on @GHC.TypeLits.Nat@:
@@ -47,7 +47,8 @@
 extra-source-files:  README.md
                      CHANGELOG.md
 cabal-version:       >=1.10
-tested-with:         GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.1
+tested-with:         GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.1, GHC == 8.4.2,
+                     GHC == 8.5.0
 
 source-repository head
   type: git
@@ -68,8 +69,8 @@
                        ghc                       >= 7.10    && <8.6,
                        ghc-prim                  >= 0.5     && <1.0,
                        ghc-tcplugins-extra       >= 0.2,
-                       ghc-typelits-knownnat     >= 0.4     && <0.5,
-                       ghc-typelits-natnormalise >= 0.5     && <0.6,
+                       ghc-typelits-knownnat     >= 0.5     && <0.6,
+                       ghc-typelits-natnormalise >= 0.6     && <0.7,
                        integer-gmp               >= 1.0     && <1.1,
                        transformers              >= 0.4.2.0 && <0.6
   hs-source-dirs:      src
diff --git a/src/GHC/TypeLits/Extra/Solver/Operations.hs b/src/GHC/TypeLits/Extra/Solver/Operations.hs
--- a/src/GHC/TypeLits/Extra/Solver/Operations.hs
+++ b/src/GHC/TypeLits/Extra/Solver/Operations.hs
@@ -25,6 +25,8 @@
 where
 
 -- external
+import Control.Monad.Trans.Writer.Strict
+
 import GHC.Base                     (isTrue#,(==#),(+#))
 import GHC.Integer                  (smallInteger)
 import GHC.Integer.Logarithms       (integerLogBase#)
@@ -108,7 +110,7 @@
 mergeMax defs x y =
   let x' = reifyEOP defs x
       y' = reifyEOP defs y
-      z  = normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])
+      z  = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])))
   in  case isNatural z of
         Just True  -> y
         Just False -> x
@@ -118,7 +120,7 @@
 mergeMin defs x y =
   let x' = reifyEOP defs x
       y' = reifyEOP defs y
-      z  = normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])
+      z  = fst (runWriter (normaliseNat (mkTyConApp typeNatSubTyCon [y',x'])))
   in  case isNatural z of
         Just True  -> x
         Just False -> y