diff --git a/rest-core.cabal b/rest-core.cabal
--- a/rest-core.cabal
+++ b/rest-core.cabal
@@ -1,5 +1,5 @@
 name:                rest-core
-version:             0.39.0.1
+version:             0.39.0.2
 description:         Rest API library.
 synopsis:            Rest API library.
 maintainer:          code@silk.co
@@ -66,6 +66,8 @@
     , uri-encode == 1.5.*
     , utf8-string >= 0.3 && < 1.1
     , uuid >= 1.2 && < 1.4
+  if impl(ghc < 8.0)
+    build-depends: semigroups == 0.18.*
 
 test-suite rest-tests
   ghc-options:       -Wall
diff --git a/src/Rest/Driver/RestM.hs b/src/Rest/Driver/RestM.hs
--- a/src/Rest/Driver/RestM.hs
+++ b/src/Rest/Driver/RestM.hs
@@ -16,9 +16,10 @@
 
 import Control.Applicative
 import Control.Monad.Reader
-import Control.Monad.Writer
+import Control.Monad.Writer (WriterT (..), tell)
 import Data.CaseInsensitive (CI, mk)
 import Data.HashMap.Strict (HashMap)
+import Data.Semigroup
 import qualified Data.ByteString.Lazy.UTF8 as UTF8
 import qualified Data.HashMap.Strict       as H