diff --git a/Changelog.markdown b/Changelog.markdown
--- a/Changelog.markdown
+++ b/Changelog.markdown
@@ -1,5 +1,8 @@
 # Changelog
 
+## 0.1.12.0
+* Support for GHC 8.4
+
 ## 0.1.11.0
 * Improved documentation
 * Fixed exists_table
diff --git a/postgresql-simple-migration.cabal b/postgresql-simple-migration.cabal
--- a/postgresql-simple-migration.cabal
+++ b/postgresql-simple-migration.cabal
@@ -1,5 +1,5 @@
 name:                       postgresql-simple-migration
-version:                    0.1.11.0
+version:                    0.1.12.0
 synopsis:                   PostgreSQL Schema Migrations
 homepage:                   https://github.com/ameingast/postgresql-simple-migration
 Bug-reports:                https://github.com/ameingast/postgresql-simple-migration/issues
@@ -70,5 +70,5 @@
     build-depends:          base                        >= 4.6      && < 5.0,
                             bytestring                  >= 0.10     && < 0.11,
                             postgresql-simple           >= 0.4      && < 0.6,
-                            hspec                       >= 2.2      && < 2.5,
+                            hspec                       >= 2.2      && < 2.6,
                             postgresql-simple-migration
diff --git a/src/Database/PostgreSQL/Simple/Migration.hs b/src/Database/PostgreSQL/Simple/Migration.hs
--- a/src/Database/PostgreSQL/Simple/Migration.hs
+++ b/src/Database/PostgreSQL/Simple/Migration.hs
@@ -255,6 +255,11 @@
     -- ^ Performs a series of 'MigrationCommand's in sequence.
     deriving (Show, Eq, Read, Ord)
 
+#if __GLASGOW_HASKELL__ >= 804
+instance Semigroup MigrationCommand where
+    (<>) = mappend
+#endif
+
 instance Monoid MigrationCommand where
     mempty = MigrationCommands []
     mappend (MigrationCommands xs) (MigrationCommands ys) = MigrationCommands (xs ++ ys)