Countdown to G-Day: Phase 5 of the User-Agent reduction


10/18/2022 3:15 PM

User Agent Client Hints Version 4 Google Device Detection News

Chrome 107 is the first Chrome version to contain reduced platform information within desktop User-Agents

We come bearing bad news. The next phase of Google’s User-Agent Reduction is here, and it’s a big one.

Update: Google has provided an update on the User-Agent reduction timeline. Please refer to our Google Q4 report blog for more information.

Get support for the changes

Phase 5: reduced platform information in desktop User-Agents

According to Google’s proposed rollout of the User-Agent Reduction, Phase 5 begins on 25 October 2022 with the release of Chrome 107.

It will be the first Chrome version to limit the desktop information within the User-Agent string: the platform information (such as Windows 10 or macOS 10.15.7) will be replaced with set characters of which the value will never change.

Desktop (user on Windows 8.1, for example)
Previous UA Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Safari/537.36
Phase 5 UA Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Safari/537.36

Why is this happening?

In 2020, Google introduced their alternative to the User-Agent HTTP request header: User-Agent Client Hints (UA-CH).

This HTTP header is unique to Google, and is only available within Chromium-based browsers, such as Chrome or Edge.

Google staggered their rollout of UA-CH (which was completed in March 2021) and are now turning their focus onto rolling out the reduced User-Agent. This process began in May 2021.

User-Agent reduction phase Date Summary of the changes
Phase 1 September 2021 Chrome 92. Warn about accessing navigator.userAgent, navigator.appVersion, and navigator.platform in DevTools.
Phase 2 October 2021 to March 2022 Chrome 95 to Chrome 100. Launch of reduced User-Agent origin trial for users to provide feedback.
Phase 3 March 2022 Chrome 100. Launch a reverse origin trial (opt in).
Phase 4 April 2022 Chrome 101. Reduction of Chrome version number present in the User-Agent.
Phase 5 October 2022 Chrome 107. Reduction of platform and version information present in desktop User-Agents.
Phase 6 February 2023 Chrome 110. Reduction of device model and Android version information present in Android mobile and tablet User-Agents.
Phase 7 May 2023 Chrome 113. All page loads receive the reduced User-Agent.

So far, there hasn’t been a wide adoption of UA-CH from other browsers or vendors, except for Microsoft (who decided that Windows 11 should only be detectable via UA-CH).

Chrome browsers make up 65% of the browser share worldwide, so that’s a lot of users whose platform you’d be unable to identify without UA-CH!

What do I need to do?

While Chrome 107 has been available as part of a staggered Canary, Dev, then Beta release, 25 October 2022 will bring a widespread Stable release of Chrome with the reduced desktop User-Agent.

On this date, most Chrome users will be prompted to update their browsers to the latest version, so you will see an influx of Chrome 107 users accessing your websites or ads. You will not be able to identify what platform desktop users of Chrome 107 are on, unless you have configured your systems for User Agent Client Hints. Please refer to our UA-CH documentation for instructions on how to do this within cloud or on-premise scenarios.

New customers

If you currently utilize the User-Agent for device detection in your business, you need to also introduce User-Agent Client Hints support to run alongside the User-Agent.

The best way to obtain User-Agent Client Hints Device Detection support is by getting started with Version 4.4 of 51Degrees.

V3 customers

Version 3 of 51Degrees does not contain User-Agent Client Hints support. UA-CH are a big change for the industry and their complexities warranted a change in version number within our service.

Getting started with UA-CH support will vary depending on whether you are a cloud or on-premise customer. For full instructions, please refer to our Version 4.4 blog.

Upgrade to Version 4

V4 customers

For Version 4 on-premise users, you will need to ensure you’re using Version 4.4 of our packages alongside the latest data files. The packages can be found on GitHub. We also recommend enabling usage sharing within your environment; it will allow our machine-learning algorithm to improve its accuracy regarding the relatively new UA-CH headers.

If you are a Version 4 cloud customer of ours, you will need to re-generate your Resource Key via our Configurator to include the following properties:

  • SetHeaderHardwareAccept-CH

  • SetHeaderPlatformAccept-CH

  • SetHeaderBrowserAccept-CH

Please refer to our UA-CH documentation for examples on how to use these properties in the Pipeline.

The future

After Phase 5, mobile and tablet User-Agents will get their time to shine. Phase 6, commencing on 1 February 2023 will see a reduction of information within both mobile and table User-Agent strings.

Add 1 February 2023 to your diary as that's when the next major stage of the User-Agent Reduction will occur.

From February, android version information within mobile and tablet User-Agents will be replaced with “10”, and the device model information will be replaced with “K”. It’ll be impossible to tell via the User-Agent alone what specific device your users are on.

Mobile (user on Samsung Galaxy, for example)
Previous UA Mozilla/5.0 (Linux; Android 9; SM-A205U) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Mobile Safari/537.36
Phase 6 UA Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/ Mobile Safari/537.36

The reduction of the User-Agent in Chrome browsers will be complete with Phase 7 and the release of Chrome 113, when all Chrome User-Agents will be in their final reduced states. This is currently scheduled for early April 2023, or “G-Day” as we’ve called it.

We’ve said it before and we’ll say it again: we’re not happy Google is forcing this change on the industry, but unfortunately all we can do is work to the timelines they have given us.

Rather than wait and see what impact Google’s imposed changes will have on your business, we recommend getting ready as soon as possible in order to maintain a high level of accuracy and low levels of last-minute stress!

If you have any questions about User-Agent Client Hints or your current subscription with us, please do get in touch and we’d be happy to help.

Further reading