diff --git a/zircon.info.yml b/zircon.info.yml
index 9d3fc19..6f7f20c 100644
--- a/zircon.info.yml
+++ b/zircon.info.yml
@@ -4,7 +4,7 @@ base theme: classy
 description: 'A flexible, recolorable theme with many regions and a responsive, mobile-first layout.'
 package: Core
 version: 8.1.3
-core: 8.x
+core_version_requirement: '^8 || ^9'
 libraries:
   - zircon/global-styling
 regions: