Countdown to G-Day: the User-Agent reduction is complete


6/1/2023 1:00 PM

User Agent Client Hints Google Device Detection Industry Web

Device detection upgrade needed now

The User-Agent reduction has progressed to the final phase. All web device detection solutions that don’t support the User-Agent reduction and User-Agent Clients Hint (UA-CH) must now be upgraded if they are to continue to function.

For those yet to switch, follow the guides below:

How can I prepare for the User-Agent reduction?

Many individuals and businesses are still using free, open source User-Agent parsers. These parsers are built to only detect the User-Agent HTTP request header, potentially returning incorrect results thanks to the changes made in Phases 5 and 6 of the User-Agent reduction.

51Degrees supports detection through both the User-Agent string and User-Agent Client Hints. We have different solutions available for companies to make the switch.

Free solutions

Our 51Degrees UAParser takes the popular UAParser.js package and improves it with support for User-Agent Client Hints. You can find the code and instructions to migrate on GitHub or npm.

Alternatively, you can integrate our free Cloud solution into your products. To get started, you will need to create a Resource Key with your desired properties. If you wish to use our free on-premise service, you can download our free data file.

You may find during the creation of your Resource Key you have selected a paid device property – you will need to select a pricing plan that suits your use case. You will be granted a License Key.

With these, you can then use the 51Degrees service in the cloud or on-premise.

If you are interested in a paid solution, please get in touch with our sales team and mention your use case. They will suggest the best solution for your business.


History of the User-Agent reduction

Since our previous blogs on the User-Agent reduction, a few changes have occurred.

Phase 7: all page loads receive the reduced User-Agent

Phase 7 of the UA reduction was scheduled to start with the release of Chrome 113. According to the Chrome Roadmap, this occurred on 26 April 2023.

Chrome 113 signifies the end of the User Agent reduction, as the reverse Origin Trial will end (stakeholders could trial out the User-Agent reduction before general release to provide feedback) and all page loads will receive the reduced User-Agent string.

Phase 6: the changing timeline

This year, our focus has been on Phase 6 of the User-Agent reduction. In Phase 6, mobile and tablet Chrome User-Agents would see the Android and device model information replaced with a fixed value of “Android 10; K”.

At the end of January, we were fully geared up for Phase 6 to finish in April 2023 – this was following a timeline provided by Google to the UK’s Competition and Markets Authority (CMA).

Source: Google's Q4 Progress report

Imagine our surprise when 14 February came around and there was no Chrome 110 in sight. Turns out Google continually pushed back the timeline throughout the Chrome 110 rollout.

Source: Google Blink thread

Compared to the original timeline provided by Google to the CMA, Phase 6 of the User-Agent reduction should've concluded on 11 April, but it actually ended on 11 May – over four weeks after the promised date.

The CMA report and User-Agent Client Hints latency

Back in June 2022, we raised concern with the level of latency within User-Agent Client Hints (UA-CH).

In the Q1 2023 report to the CMA from Google (released end of April 2023), Google was requested to carry out additional testing of latency incurred when critical hints are requested via UA-CH. The findings “indicate a modest latency impact”.

We are pleased that stakeholder feedback was listened to and actioned upon by both the CMA and Google. We look forward to future improvements to the User-Agent Client Hints latency following additional feedback from advertisers, ad tech businesses, civil groups, and other interested parties.

The future

In 2022, the UK’s CMA accepted Google’s offer to provide commitments regarding the Privacy Sandbox proposals. The commitments will continue for six years unless they have been released at an earlier date. This will take us to 2028 at the latest.

There is still time to make your feedback known on Google’s User-Agent reduction and User-Agent Client Hints. The CMA are keen to hear from stakeholders on the UA-CH latency in particular.

You can supply feedback via:

Alternatively, ensure your digital business is not impacted by Google’s changes to the web. The 51Degrees services have support for both the User-Agent reduction and User-Agent Client Hints.

Get started with 51Degrees