Deprecations and removals in Chrome 100

Chrome 100 beta was released on March 3, 2022 and is expected to become the stable version in late March, 2022.

# Last Version for Unreduced User-Agent String

Chromium 100 will be the last version to support an unreduced User-Agent string by default (as well as the related navigator.userAgent, navigator.appVersion, and navigator.platform DOM APIs). The origin trial that allowed sites to test the fully reduced User-Agent will end on April 19, 2022. After that date, the User-Agent String will be gradually reduced. To review the whole schedule, see Chromium Blog: User-Agent Reduction Origin Trial and Dates. Sites that need more time to test or migrate to User-Agent Client Hints can enroll in the deprecation origin trial scheduled from Chrome 100 to 113, inclusive. In contrast to the first origin trial, which previews the fully reduced User-Agent string, the deprecation trial maintains the legacy User-Agent. The deprecation trial is expected to end in late May of 2023.

This is part of a strategy to replace use of the User-Agent string with the new User-Agent Client Hints API. To learn about User-Agent Client Hints, see Migrate to User-Agent Client Hints and Improving user privacy and developer experience with User-Agent Client Hints.

# Deprecation policy

To keep the platform healthy, we sometimes remove APIs from the Web Platform which have run their course. There can be many reasons why we would remove an API, such as:

• They are superseded by newer APIs.
• They are updated to reflect changes to specifications to bring alignment and consistency with other browsers.
• They are early experiments that never came to fruition in other browsers and thus can increase the burden of support for web developers.

Some of these changes will have an effect on a very small number of sites. To mitigate issues ahead of time, we try to give developers advanced notice so they can make the required changes to keep their sites running.

Chrome currently has a process for deprecations and removals of API's, essentially:

• Announce on the blink-dev mailing list.
• Set warnings and give time scales in the Chrome DevTools Console when usage is detected on the page.
• Wait, monitor, and then remove the feature as usage drops.

You can find a list of all deprecated features on chromestatus.com using the deprecated filter and removed features by applying the removed filter. We will also try to summarize some of the changes, reasoning, and migration paths in these posts.