Countdown to G-Day: Phase 6 of the User-Agent reduction

This is a fundamental change that will affect device detection as you know it

The penultimate phase of Google’s User-Agent reduction will roll out in just three weeks – this time, Chrome mobile and tablet User-Agents will change.

Update: Google has provided an update on the Phase 6 User-Agent reduction timeline. Please refer to our Google Q4 report blog for more information.

Phase 6: reduced device model information in mobile and tablet User-Agents

Phase 6 of the User-Agent reduction begins with Chrome 110 which is due for release on 1 February 2023. It will be the first Chrome version that has information removed from mobile and tablet User-Agents.

The device model and android version information will not be in the Chrome User-Agent.

Google will instead replace this information in the User-Agent with a fixed value. Let's look at an example with a Samsung Galaxy mobile User-Agent. The device model information (SM-A205U) will be replaced with a fixed value of K, and the android version (Android 9) will be replaced with a fixed value of Android 10.

In essence, you will not be able to tell the difference between different mobiles devices, whether it’s a Samsung Galaxy S21 or a Huawei Mate 50 Pro. This change on 1 February will affect all mobiles and tablets that are using Chrome 110 and later.

The only way to accurately detect these devices is through User-Agent Client Hints.

User-Agent Client Hints

Google created User-Agent Client Hints (UA-CH), an alternative to the User-Agent HTTP request header. Google gradually introduced UA-CH to their Chrome browser and has now moved to reducing information available within the Chrome User-Agent.

We've blogged extensively every step of the way: from the announcement of User-Agent Client Hints to the different phases of the User-Agent reduction.

The time to act is NOW!

This is the most crucial point in the User-Agent reduction. Chrome dominates the browser share worldwide, making up 65% of the browser share. The changes coming on 1 February will therefore affect 65% of traffic to your websites or products.

If your device detection is not updated for this change, you may see drastic impact to your business. If you use a free, open-source, or internal User-Agent parser, it may no longer work as it does not contain User-Agent Client Hint data. If you rely on the User-Agent within your website, the changes to Chrome may break your site.

You need to ensure you have support for User-Agent Client Hints within your device detection, analytics, products, and websites.

Prepare for the User-Agent reduction

The best way to prepare for the User-Agent reduction is to ensure your web offerings are configured to receive User-Agent Client Hints data.

Version 4.4 of 51Degrees contains full support for UA-CH. Version 3 does not contain support for the User-Agent reduction nor User-Agent Client Hints, so Version 3 customers will need to upgrade to Version 4.4.

If you are a new customer, or a Version 3 customer of ours, you can follow these instructions to get started with 51Degrees. Alternatively, you can get in touch and we'll happily help you out.

Google's User-Agent reduction is due to conclude with Chrome 113, scheduled for end of April 2023 – we've been referring to this date as “G-Day”. All page loads using Chrome will receive the reduced User-Agent.

This is not a problem that will go away: as more people update to the latest version of Chrome, you need to prepare now before it's too late.