diff --git a/stack.yaml b/stack.yaml
index a45652dd..579cbb62 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -15,5 +15,4 @@ extra-deps:
 - hspec-core-2.3.2
 - hspec-wai-0.8.0
 - hspec-expectations-0.8.2
-- call-stack-0.1.0
-resolver: lts-6.0
+resolver: lts-6.27