diff --git a/Mainate.cabal b/Mainate.cabal
index 34d37ed..8db51e3 100644
--- a/Mainate.cabal
+++ b/Mainate.cabal
@@ -21,6 +21,6 @@ library
   exposed-modules:   Stream
   -- other-modules:
   -- other-extensions:
-  build-depends:       base >=4.12 && <4.13
+  build-depends:       base >=4.9 && <4.13
   hs-source-dirs:      src
   default-language:    Haskell2010
diff --git a/src/Stream.hs b/src/Stream.hs
index 7fefe2c..be6b61c 100644
--- a/src/Stream.hs
+++ b/src/Stream.hs
@@ -6,12 +6,10 @@ import Data.List (intercalate)
 
 data Stream a = Stream [(a, Stream a)] deriving Show
 
-instance Semigroup (Stream a) where
-  (<>) (Stream []) b = b
-  (<>) (Stream pairs) b = Stream $ (\(a, stream) -> (a, stream <> b)) <$> pairs
-
 instance Monoid (Stream a) where
   mempty = fromList []
+  mappend (Stream []) b = b
+  mappend (Stream pairs) b = Stream $ (\(a, stream) -> (a, stream `mappend` b)) <$> pairs
 
 fromList :: [a] -> Stream a
 fromList [] = Stream []