diff --git a/stack.yaml b/stack.yaml
index 4393a85..a16d2f5 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,9 +1,8 @@
-resolver: lts-19.20
+resolver: lts-21.0
 packages:
 - '.'
 save-hackage-creds: false
 
 extra-deps:
-- fortran-src-0.12.0
-- fortran-src-extras-0.4.0
-- yaml-0.11.8.0
+- fortran-src-0.15.0
+- fortran-src-extras-0.5.0