diff --git a/stack.yaml b/stack.yaml
index 8a9751193..254318e76 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -2,7 +2,7 @@
 # For advanced use and comprehensive documentation of the format, please see:
 # https://docs.haskellstack.org/en/stable/yaml_configuration/
 
-resolver: lts-20.16
+resolver: lts-21.4
 
 packages:
 - .