diff --git a/tests/manual/haskell/simple/stack.yaml b/tests/manual/haskell/simple/stack.yaml
index 9f5c8c628b2..4b8c90d83d1 100644
--- a/tests/manual/haskell/simple/stack.yaml
+++ b/tests/manual/haskell/simple/stack.yaml
@@ -15,7 +15,7 @@
 # resolver:
 #  name: custom-snapshot
 #  location: "./custom-snapshot.yaml"
-resolver: lts-7.24
+resolver: lts-21.1
 
 # User packages to be built.
 # Various formats can be used as shown in the example below.