Edge 153 Starts Dropping unload Handlers: 60% of Page Loads, Climbing to 100%

Edge 153.0.4234.32 reached Stable on September 10, 2026. In Edge 152 and 153, unload handlers stop firing for 60% of page loads unless a site explicitly enables them through Permissions Policy, and Microsoft's notes put the rollout at 80% in Edge 154 and 100% in Edge 155.

The opt-in is a policy-controlled feature token named unload. The same notes say unload can disqualify a page from the back/forward cache, and that the platform's long-term direction is to remove support for it. Chrome's published schedule differs from Edge's: Chrome 151 (July 28, 2026) 60%, Chrome 152 (August 25, 2026) 80%, Chrome 154 (September 22, 2026) 100%. The two vendors disagree on which milestone reaches each share.

A handler that runs during unload blocks the back/forward cache, which is the reason for the removal. If your analytics, session teardown, or state persistence lives in unload, it already skips 60% of page loads on current Edge builds, and that share only grows.

Replace unload handlers with pagehide or visibilitychange this week; waiting for 100% buys you nothing. Confirm that any beacon or state save still runs when a page is restored from the back/forward cache. Then test on Edge 153 and on Chrome 151 or later, where the reduced firing rate is already live.