diff --git a/stack.lts6.yaml b/stack.lts6.yaml
index 4208be350..4af30de8f 100644
--- a/stack.lts6.yaml
+++ b/stack.lts6.yaml
@@ -11,3 +11,4 @@ extra-deps:
 - data-default-0.6.0
 - http-client-0.5.0
 - http-client-tls-0.3.0
+resolver: lts-6.5