diff --git a/build-constraints.yaml b/build-constraints.yaml
index 5bd3f513..65c05960 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -947,6 +947,9 @@ package-flags:
     jose-jwt:
         doctest: false
 
+    arbtt:
+        old-locale: true
+
 # By skipping a test suite, we do not pull in the build dependencies
 skipped-tests:
     - ReadArgs # old version of hspec