diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,10 @@
 # Revision history for servant-event-stream
 
-## 0.2.0.0 -- 2021-04-x
+## 0.2.1.0 -- 2021-04-21
+
+* Import `Data.Semigroup` for base < 4.11.0
+
+## 0.2.0.0 -- 2021-04-20
 
 * `Servant.EventStream` was moved to `Servant.API.EventStream` to adhere existing [upstream layout](https://hackage.haskell.org/package/servant-0.18.2/docs/Servant-API-Stream.html).
 
diff --git a/servant-event-stream.cabal b/servant-event-stream.cabal
--- a/servant-event-stream.cabal
+++ b/servant-event-stream.cabal
@@ -1,6 +1,6 @@
 cabal-version:       >=1.10
 name:                servant-event-stream
-version:             0.2.0.0
+version:             0.2.1.0
 stability:           alpha
 
 synopsis:            Servant support for Server-Sent events
diff --git a/src/Servant/API/EventStream.hs b/src/Servant/API/EventStream.hs
--- a/src/Servant/API/EventStream.hs
+++ b/src/Servant/API/EventStream.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP                        #-}
 {-# LANGUAGE DataKinds                  #-}
 {-# LANGUAGE DeriveGeneric              #-}
 {-# LANGUAGE FlexibleContexts           #-}
@@ -20,6 +21,9 @@
 
 import           Control.Lens
 import           Data.Binary.Builder            ( toLazyByteString )
+#if !MIN_VERSION_base(4,11,0)
+import           Data.Semigroup
+#endif
 import           Data.Text                      ( Text )
 import qualified Data.Text                     as T
 import           GHC.Generics                   ( Generic )