diff --git a/Text/PrettyPrint/Mainland.hs b/Text/PrettyPrint/Mainland.hs
--- a/Text/PrettyPrint/Mainland.hs
+++ b/Text/PrettyPrint/Mainland.hs
@@ -82,11 +82,12 @@
                  posFile,
                  posLine)
 import qualified Data.Map as Map
-#if MIN_VERSION_base(4,5,0)
+#if !(MIN_VERSION_base(4,9,0))
 import Data.Monoid (Monoid(..), (<>))
-#else /* !MIN_VERSION_base(4,5,0) */
-import Data.Monoid (Monoid(..))
-#endif /* !MIN_VERSION_base(4,5,0) */
+#endif /* !(MIN_VERSION_base(4,9,0)) */
+#if MIN_VERSION_base(4,9,0) && !(MIN_VERSION_base(4,11,0))
+import Data.Semigroup (Semigroup(..))
+#endif
 import qualified Data.Set as Set
 import Data.String (IsString(..))
 import qualified Data.Text as T
@@ -122,9 +123,16 @@
          -- | Calculate document based on current nesting
          | Nesting (Int -> Doc)
 
+#if MIN_VERSION_base(4,9,0)
+instance Semigroup Doc where
+    (<>) = Cat
+#endif
+
 instance Monoid Doc where
     mempty  = empty
+#if !(MIN_VERSION_base(4,11,0))
     mappend = Cat
+#endif
 
 instance IsString Doc where
     fromString s = string s
diff --git a/mainland-pretty.cabal b/mainland-pretty.cabal
--- a/mainland-pretty.cabal
+++ b/mainland-pretty.cabal
@@ -1,11 +1,11 @@
 name:           mainland-pretty
-version:        0.6.1
+version:        0.6.2
 cabal-version:  >= 1.6
 license:        BSD3
 license-file:   LICENSE
 copyright:      (c) 2006-2011 Harvard University
                 (c) 2011-2012 Geoffrey Mainland
-                (c) 2015-2017 Drexel University
+                (c) 2015-2018 Drexel University
 author:         Geoffrey Mainland <mainland@drexel.edu>
 maintainer:     Geoffrey Mainland <mainland@drexel.edu>
 stability:      alpha
@@ -14,12 +14,12 @@
 category:       Text
 synopsis:       Pretty printing designed for printing source code.
 description:    Pretty printing designed for printing source code based on
-		Wadler's paper /A Prettier Printer/. The main advantage of this
-		library is its ability to automatically track the source
-		locations associated with pretty printed values and output
-		appropriate #line pragmas and its ability to produce output
+                Wadler's paper /A Prettier Printer/. The main advantage of this
+                library is its ability to automatically track the source
+                locations associated with pretty printed values and output
+                appropriate #line pragmas and its ability to produce output
                 in the form of lazy text using a builder.
-tested-with:    GHC==7.4.2, GHC==7.6.3, GHC==7.8.3, GHC==7.10.3, GHC==8.0.2, GHC==8.2.1
+tested-with:    GHC==7.4.2, GHC==7.6.3, GHC==7.8.3, GHC==7.10.3, GHC==8.0.2, GHC==8.2.2, GHC==8.4.1
 
 build-type:     Simple