What causes a service worker serving an old build?

A service worker cached the old files and keeps serving them, so players do not get the new build until the worker updates and the cache is invalidated.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Service Worker Serving an Old Game Build

Quick answer: Version your cache name so the worker replaces old caches on update, claim clients and skip waiting to activate immediately, and clear outdated caches in the activate event.

Players stuck on an old version of your web game are usually being served by a service worker cache that never invalidated. Versioning the cache and updating the worker fixes it. Here is how.

How to fix it

1. Version the cache name

Include a version in the cache name and delete old caches in the worker's activate event. When you ship a build, bump the version so the worker fetches and caches the new files.

2. Skip waiting and claim clients

Call skipWaiting on install and clients.claim on activate so the new worker takes over immediately instead of waiting for every tab to close. Otherwise updates lag for active players.

3. Clear outdated caches

In activate, enumerate caches and delete any that do not match the current version. This removes the stale build so the next load is the fresh one.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every HTML5 error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.