diff --git a/pkgs/development/libraries/haskell/yesod-core/default.nix b/pkgs/development/libraries/haskell/yesod-core/default.nix
index 5eaaa316ecf..bd1116267fa 100644
--- a/pkgs/development/libraries/haskell/yesod-core/default.nix
+++ b/pkgs/development/libraries/haskell/yesod-core/default.nix
@@ -1,17 +1,17 @@
-{ cabal, aeson, attoparsecConduit, blazeBuilder, blazeHtml
+{ cabal, aeson, async, attoparsecConduit, blazeBuilder, blazeHtml
 , blazeMarkup, caseInsensitive, cereal, clientsession, conduit
 , cookie, dataDefault, failure, fastLogger, hamlet, hspec
-, httpTypes, HUnit, liftedBase, monadControl, monadLogger, parsec
-, pathPieces, QuickCheck, random, resourcet, safe, shakespeare
-, shakespeareCss, shakespeareI18n, shakespeareJs, text, time
-, transformers, transformersBase, unixCompat, vector, wai, waiExtra
-, waiLogger, waiTest, warp, yesodRoutes
+, httpTypes, HUnit, liftedBase, monadControl, monadLogger, network
+, networkConduit, parsec, pathPieces, QuickCheck, random, resourcet
+, safe, shakespeare, shakespeareCss, shakespeareI18n, shakespeareJs
+, text, time, transformers, transformersBase, unixCompat, vector
+, wai, waiExtra, waiLogger, waiTest, warp, yesodRoutes
 }:
 
 cabal.mkDerivation (self: {
   pname = "yesod-core";
-  version = "1.2.6.7";
-  sha256 = "09vxi7fkiakr58ifa6ribsqq1p6fmqclznj38vhl5rdfalm7yivg";
+  version = "1.2.7";
+  sha256 = "1gkpx0d7hyvn45254aj40iy4k0bf3kkrvmxnw3q1mvqc3k1kdxqn";
   buildDepends = [
     aeson attoparsecConduit blazeBuilder blazeHtml blazeMarkup
     caseInsensitive cereal clientsession conduit cookie dataDefault
@@ -22,9 +22,9 @@ cabal.mkDerivation (self: {
     yesodRoutes
   ];
   testDepends = [
-    blazeBuilder conduit hamlet hspec httpTypes HUnit liftedBase
-    QuickCheck random resourcet shakespeareCss shakespeareJs text
-    transformers wai waiTest
+    async blazeBuilder conduit hamlet hspec httpTypes HUnit liftedBase
+    network networkConduit QuickCheck random resourcet shakespeareCss
+    shakespeareJs text transformers wai waiTest
   ];
   jailbreak = true;
   meta = {