diff --git a/platform/webext/manifest.json b/platform/webext/manifest.json
index ad02944..21152ab 100644
--- a/platform/webext/manifest.json
+++ b/platform/webext/manifest.json
@@ -2,7 +2,7 @@
     "applications": {
         "gecko": {
             "id": "uMatrix@raymondhill.net",
-            "strict_min_version": "56.*"
+            "strict_min_version": "56.0a1"
         }
     },
     "author": "Raymond Hill",