diff --git a/stack-ghc-7.8.4.yaml b/stack-ghc-7.8.4.yaml
index 3581c6a9..ce2d7269 100644
--- a/stack-ghc-7.8.4.yaml
+++ b/stack-ghc-7.8.4.yaml
@@ -19,4 +19,5 @@ extra-deps:
 - engine-io-wai-1.0.3
 - socket-io-1.3.3
 - stm-delay-0.1.1.1
+- control-monad-omega-0.3.1
 resolver: lts-2.22