diff --git a/stack.yaml b/stack.yaml
index 660e7897..039c8657 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,7 +1,7 @@
 # This stack.yaml is used to build xmonad-contrib with released versions
 # of X11 and xmonad
 
-resolver: lts-20.16
+resolver: lts-21.6
 
 packages:
 - ./