diff --git a/build-constraints.yaml b/build-constraints.yaml
index 2832d587..d5587ea5 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -589,6 +589,7 @@ packages:
     "Joey Hess <id@joeyh.name> @joeyh":
         - git-annex
         - Win32-extras
+        - concurrent-output
 
     "Ketil Malde":
         - biocore