diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+0.4.1.2 - 2018-06-27
+--------------------
+
+Fix compatibility with GHC 8.4
+
+
 0.4.1.1 - 2015-11-10
 --------------------
 
diff --git a/Test/Tasty/Runners/Html.hs b/Test/Tasty/Runners/Html.hs
--- a/Test/Tasty/Runners/Html.hs
+++ b/Test/Tasty/Runners/Html.hs
@@ -16,7 +16,8 @@
 import Control.Concurrent.STM (atomically, readTVar)
 import qualified Control.Concurrent.STM as STM(retry)
 import Data.Maybe (fromMaybe)
-import Data.Monoid (Monoid(mempty,mappend), (<>), Sum(Sum,getSum))
+import Data.Monoid (Monoid(mempty,mappend), Sum(Sum,getSum))
+import Data.Semigroup ((<>))
 import Data.Typeable (Typeable)
 import GHC.Generics (Generic)
 import System.FilePath ((</>))
@@ -112,9 +113,12 @@
                        , htmlRenderer :: Markup
                        } deriving (Generic)
 
+instance Semigroup Summary where
+  (<>) = mappenddefault
+
 instance Monoid Summary where
   mempty = memptydefault
-  mappend = mappenddefault
+  mappend = (<>)
 
 -- | A 'Traversal' composed of a 'Summary' and a test count.
 type SummaryTraversal = Traversal (Compose (StateT Int IO) (Const Summary))
diff --git a/tasty-html.cabal b/tasty-html.cabal
--- a/tasty-html.cabal
+++ b/tasty-html.cabal
@@ -1,5 +1,5 @@
 name:                tasty-html
-version:             0.4.1.1
+version:             0.4.1.2
 synopsis:            Render tasty output to HTML
 description:         A tasty ingredient to output test results in HTML5.
 license:             MIT
@@ -33,6 +33,7 @@
     generic-deriving >= 1.6.2,
     mtl >= 2.1.2,
     stm >= 2.4.2,
+    semigroups,
     tagged >= 0.7,
     tasty >= 0.10.1,
     text >= 1.0,