diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6f025d0..1af76b9 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -51,7 +51,7 @@ jobs:
     environment:
       # FIXME: https://circleci.com/gh/thoughtbot/yesod-auth-oauth2/115
       LINT: "0"
-      STACK_ARGUMENTS: --resolver lts-9.21
+      STACK_ARGUMENTS: --stack-yaml stack-lts-9.21.yaml
   build_8.2.2:
     <<: *stack_build
     environment:
diff --git a/stack-lts-9.21.yaml b/stack-lts-9.21.yaml
new file mode 100644
index 0000000..4832977
--- /dev/null
+++ b/stack-lts-9.21.yaml
@@ -0,0 +1,4 @@
+---
+resolver: lts-9.21
+extra-deps:
+  - load-env-0.1.2