diff --git a/Casks/f/firefox@beta.rb b/Casks/f/firefox@beta.rb
index 8759ee9e3cfb5..73baacc4cd718 100644
--- a/Casks/f/firefox@beta.rb
+++ b/Casks/f/firefox@beta.rb
@@ -99,7 +99,7 @@
   livecheck do
     url "https://product-details.mozilla.org/1.0/firefox_versions.json"
     strategy :json do |json|
-      json["FIREFOX_DEVEDITION"]
+      json["LATEST_FIREFOX_RELEASED_DEVEL_VERSION"]
     end
   end