diff --git a/deb/stack.yaml b/deb/stack.yaml
index f714fe3e2..3f84be738 100644
--- a/deb/stack.yaml
+++ b/deb/stack.yaml
@@ -18,5 +18,5 @@ extra-deps:
 - 'cmark-0.5.0'
 - 'pandoc-types-1.16.0.1'
 # Use older aeson to avoid excessive memory use in compilation:
-- 'aeson-0.8.0.2
+- 'aeson-0.8.0.2'
 resolver: lts-4.0