diff --git a/flags-applicative.cabal b/flags-applicative.cabal
--- a/flags-applicative.cabal
+++ b/flags-applicative.cabal
@@ -1,5 +1,5 @@
 name:                flags-applicative
-version:             0.0.4.2
+version:             0.0.4.3
 synopsis:            Applicative flag parsing
 description:         https://github.com/mtth/flags-applicative
 homepage:            https://github.com/mtth/flags-applicative
@@ -16,7 +16,7 @@
 library
   hs-source-dirs:      src
   exposed-modules:     Flags.Applicative
-  build-depends:       base >= 4.9 && < 5
+  build-depends:       base >= 4.8 && < 5
                      , containers >= 0.6 && < 0.7
                      , mtl >= 2.2 && < 2.3
                      , text >= 1.2 && < 1.3
@@ -30,7 +30,7 @@
       test
   ghc-options: -threaded -rtsopts -with-rtsopts=-N
   build-depends:
-      base >=4.9 && <5
+      base >=4.8 && <5
     , text >= 1.2 && < 1.3
     , hspec >=2.6 && <2.7
     , flags-applicative
@@ -40,7 +40,7 @@
   hs-source-dirs:      app
   main-is:             SimpleExample.hs
   build-depends:
-      base >=4.9 && <5
+      base >=4.8 && <5
     , text >= 1.2 && < 1.3
     , flags-applicative
   default-language:    Haskell2010
diff --git a/src/Flags/Applicative.hs b/src/Flags/Applicative.hs
--- a/src/Flags/Applicative.hs
+++ b/src/Flags/Applicative.hs
@@ -51,6 +51,7 @@
 import Data.List.NonEmpty (NonEmpty(..))
 import Data.Map.Strict (Map)
 import Data.Set (Set)
+import Data.Semigroup ((<>))
 import Data.Text (Text)
 import System.Exit (die)
 import System.Environment (getArgs)