diff --git a/stack.yaml b/stack.yaml
index 6cecc95..fb40d52 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-9.5
+resolver: lts-9.18
 flags:
   yesod-auth-oauth2:
     network-uri: true