Google’s Chrome web browser and all Chromium-based browsers including Microsoft Edge will lose support for AppCache. Starting with Chrome v85, the AppCache Support will be dropped completely. Hence, Google is strongly advising web developers to migrate off of the platform at the earliest.
Developers designing web-based apps and platforms are strongly urged to drop AppCache, a system that once allowed storing information locally for access when network connectivity was unavailable. Chrome 85 will remove support for AppCache by default.
Developers Should Migrate To ‘Service Workers’ From AppCache For Better Compatibility, Security, And Reliability?
Beginning with Chrome 85, AppCache will no longer be available in Chrome by default. Incidentally, this is not a sudden change. The Application Cache (AppCache) specification has been deprecated since December 2016, and in Chrome starting in version 79. In Chrome 70, AppCache was removed from insecure contexts. Google confirmed it planned to remove AppCache in Chrome 82. Prior to AppCache’s promised removal in Chrome 82, Google even announced a security fix that introduced the concept of a manifest scope.
The Chrome AppCache removal timeline has two upcoming important milestones. Beginning with Chrome v85, AppCache will no longer be available in Chrome by default. Developers who might still require additional time to migrate off of AppCache can sign up for a “reverse” origin trial to extend the availability of AppCache for their web apps. The origin trial will start in Chrome 84 (in advance of the default removal in Chrome 85) and will be active through Chrome 89.
AppCache will be completely gone with Chrome v90. In other words, starting with Chrome 90, AppCache will be fully removed for everyone. It will not be available even those who had signed up for the “reverse” origin trial.
Reverse Original Trial Deployment For AppCache Removal And Alternative For The Platform:
While the “reverse” origin trial officially starts with Chrome 84, developers can sign up for the same today and add the tokens to their HTML and AppCache manifests. As the web app’s audience gradually upgrades to Chrome 84, any tokens that developers already added will go into effect.
Despite the availability of the extended grace period, it is strongly advised to migrate off of AppCache. The migration procedure isn’t difficult or complex. Developers can easily test the removal of AppCache on their web apps using the ‘chrome://flags/#app-cache’ flag. The flag comprehensively simulates the removal of AppCache. This flag is available starting with Chrome 84.
Preparing for AppCache removal:
Chrome 85 removes support for AppCache by default. Most developers should migrate off AppCache now, and not wait any longer.https://t.co/cNasUVL6Bs
— Chrome Developers (@ChromiumDev) May 18, 2020
Service Workers is widely supported in current browsers. It offers a perfectly working and stable alternative to the offline experience provided by AppCache. It is important to note that Chrome will disable AppCache functionality on any page that’s loaded under the control of a Service Worker. In other words, Service Workers and AppCache are mutually exclusive. Hence, it is strongly advised not to attempt to migrate to service workers piece-by-piece.
While Google Chrome still offers some support for AppCache, Firefox and other browsers have long back completely dropped support. Firefox deprecated AppCache in release 44 (September 2015) and has removed support for it in its Beta and Nightly builds as of September 2019. Safari deprecated AppCache in early 2018.
Some Android Native App developers may have to stick to AppCache for the time being. Some developers of native Android applications use Chrome WebView to display web content. But they also sometimes rely on AppCache. It is not possible to enable a reverse origin trial for a WebView.