diff --git a/build-constraints.yaml b/build-constraints.yaml
index 534e2556..c07bdaf3 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -978,8 +978,7 @@ packages:
     "Athan Clark <athan.clark@gmail.com> @athanclark":
         - nested-routes
         - urlpath
-        # https://github.com/athanclark/markup/issues/5
-        # - markup
+        - markup
         - webpage
 
     "Fumiaki Kinoshita <fumiexcel@gmail.com> @fumieval":