Intent to Extend Origin Trial: AppCache

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Adrienne Walker

Jan 22, 2021, 1:57:40 PM1/22/21
to blink-dev

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As a part of the deprecation and removal process for AppCache, we would like to allow developers to sign up for a reverse origin trial so that, if needed, they can have more time to transition their AppCache usage over to service workers.

The reasoning for AppCache removal is documented in the blink-dev discussion thread links below.

Previous Intent Threads

Blink component


Goals for experimentation

Gate the AppCache feature behind an origin trial to give developers who are still using it a chance to transition off of it while not making it available by default.

Experimental timeline

The experiment began in M83.  We started requiring origin trial tokens in M85.  We previously targeted to end the experiment in M90, but would like to extend the experiment to end in M94 instead. In M94, we plan to disable AppCache for all users.

Reasons this experiment is being extended

We are still working with large internal Google properties to complete the transition of their AppCache usage over to service workers.

Ongoing technical constraints


Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)?


Is this feature fully tested by web-platform-tests?


Link to entry on the Chrome Platform Status

Chris Harrelson

Jan 22, 2021, 2:18:04 PM1/22/21
to Adrienne Walker, blink-dev
LGTM, but: I'd like M94 to be a hard deadline. Have the Google properties agreed to meet this deadline?

Deprecating a feature like this is hard, and I can see how it takes a long time. Thanks for pushing on it.

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Adrienne Walker

Jan 22, 2021, 2:59:53 PM1/22/21
to Chris Harrelson, blink-dev
Yes, I have talked with them and they have agreed to meet this deadline.

Scott Huston

Apr 12, 2021, 10:44:05 AM4/12/21
to blink-dev, Adrienne Walker, blink-dev, Chris Harrelson
The Origin Trial for appcache appears to be working with the new Token in Windows 10/Chrome 89.0.4389.114

Functionally it works and chrome://appcache-internals shows appropriate information

On Android 11/Chrome 89.0.4389.105  chrome://appcache-internals shows no information

"Instances in: /data/user/0/ (0)"

Have filed  Issue 1197891

Mike West

Jul 27, 2021, 2:14:04 AM7/27/21
to Scott Huston, blink-dev, Adrienne Walker, Chris Harrelson
Digging this up: M93 has branched, so we're solidly in the M94 timeframe. Are y'all still on track to drop the OT in this release?


Adrienne Walker

Jul 27, 2021, 6:25:31 PM7/27/21
to Mike West, Scott Huston, blink-dev, Chris Harrelson
On Mon, Jul 26, 2021 at 11:13 PM Mike West <> wrote:
Digging this up: M93 has branched, so we're solidly in the M94 timeframe. Are y'all still on track to drop the OT in this release?

Thanks for following up.  The current reverse origin trial ends on 2021-10-05 and we previously said that M93 would be the last release with AppCache and it would be removed in M94.

In light of the changes to the Chrome release schedule, says that M95 will be cut on 2021-10-12 and that M94 will have ~3 weeks of being the stable version before the 2021-10-05 date that the origin trial stops working.  I consulted with the origin trial folks and they suggested that we follow the date rather than the milestone.  That reasoning aligned with my own intuition that moving the removal a month earlier might be unfair to any developers who were planning on a particular date.

Therefore, our plan is to not change any dates, but to move the Chrome milestone forward so that M94 is the last version of Chrome with AppCache and M95 is the version that it will be removed in.  Things are on track to make that date and there continues to be no plan to extend that date a second time.
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