diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 1.6.0.2
+
+* Support `yesod-core` 1.7
+
 ## 1.6.0.1
 
 * Update documentation from `HandlerT` to `HandlerFor` [#1703](https://github.com/yesodweb/yesod/pull/1703)
diff --git a/Yesod/EventSource.hs b/Yesod/EventSource.hs
--- a/Yesod/EventSource.hs
+++ b/Yesod/EventSource.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
+
 -- | This module contains everything that you need to support
 -- server-sent events in Yesod applications.
 module Yesod.EventSource
@@ -10,8 +11,6 @@
 
 import Blaze.ByteString.Builder (Builder)
 import Control.Monad (when)
-import Data.Functor ((<$>))
-import Data.Monoid (Monoid (..))
 import Yesod.Core
 import Data.Conduit
 import qualified Network.Wai as W
@@ -24,7 +23,7 @@
 -- set any necessary headers.
 prepareForEventSource :: MonadHandler m => m EventSourcePolyfill
 prepareForEventSource = do
-  reqWith <- lookup "X-Requested-With" . W.requestHeaders Data.Functor.<$> waiRequest
+  reqWith <- lookup "X-Requested-With" . W.requestHeaders <$> waiRequest
   let polyfill | reqWith == Just "XMLHttpRequest" = Remy'sESPolyfill
                | otherwise                        = NoESPolyfill
   addHeader "Cache-Control" "no-cache" -- extremely important!
@@ -90,7 +89,7 @@
       -- when we the connection should be closed.
       joinEvents (ev:evs) acc =
         case ES.eventToBuilder ev of
-          Just b  -> joinEvents evs (acc `Data.Monoid.mappend` b)
+          Just b  -> joinEvents evs (acc `mappend` b)
           Nothing -> (fst $ joinEvents [] acc, False)
       joinEvents [] acc = (acc, True)
 
diff --git a/yesod-eventsource.cabal b/yesod-eventsource.cabal
--- a/yesod-eventsource.cabal
+++ b/yesod-eventsource.cabal
@@ -1,6 +1,6 @@
 cabal-version:   >= 1.10
 name:            yesod-eventsource
-version:         1.6.0.1
+version:         1.6.0.2
 license:         MIT
 license-file:    LICENSE
 author:          Felipe Lessa <felipe.lessa@gmail.com>
@@ -21,7 +21,7 @@
                    , transformers
                    , wai                   >= 1.3
                    , wai-extra
-                   , yesod-core            == 1.6.*
+                   , yesod-core            >= 1.6      && < 1.8
     exposed-modules: Yesod.EventSource
     ghc-options:     -Wall