
Update: User-Agent Client Hints Progress 2022 Q4
Here is an update on the progress for 2022 Q4 (blog originally published August 2022). Google will freeze its mobile Chrome brower’s user-agent strings starting February 2023. As of 2022 Q4, 66% of Chrome desktop requests analyzed in the Mobile Overview Report (MOVR) had frozen user agent strings. This is an increase from only 14% in 2022 Q2.
If you have an open source UA Parser, you should seriously consider switching to a more accurate solution like WURFL immediately. These poorly maintained UA Parsers are inaccurate more than 22% of the time, and in February that accuracy will decline dramatically. Learn more here.

If you are already a WURFL user, make sure you
1) have installed the most updated API version and most recent device data XML snapshot file from my.scientiamobile.com
2) Opt in to request user-agent (UA) client hints by following these instructions
Since WURFL already uses UA client hints and can identify frozen user-agent strings, WURFL is ready for Google’s transition. WURFL device detection provides the highest level of accuracy and support in the industry.


User-Agent Client Hints Progress 2022 Q2
February is coming… and so are frozen Chrome mobile user-agent strings!
Google has forced a huge amount of change on the digital advertising industry recently. With their control over Google Chrome, the world’s most popular browser, and their pre-eminent control over Adwords and other forms of digital advertising, Google has the power to change some of the fundamental building blocks of the internet.
In previous blogs, we have outlined these changes and what you need to do to prepare and ensure device detection remains accurate. In this blog, we will review the timeline for converting away from user-agent strings, look at the evolution of Chrome versions, and present how many frozen user-agents are occurring.
Google Chrome Timeline and User-Agent Strings
The major change that Google is forcing in its Google Chrome updates is that User-Agent strings will no longer be actively used. Google is phasing in changes in both their Desktop and Mobile versions of Chrome. During 2022 Q2, these changes started for people who have upgraded to the latest version of Chrome.
How Many Chrome Users Update to the Latest Version?
For Google to force this transition, they must have strong adoption of new versions of Chrome. Given Google’s poor track record on forcing updates to the Android operating system for smartphones, we wanted to check and see how frequently Chrome successfully updated.
ScientiaMobile’s Mobile Overview Report (MOVR) evaluates 200 million requests each month from various devices and browsers, including Chrome. With Desktop Chrome, 82% of versions evaluated were the most recent, supported version. On Android Smartphones, the number was even higher at 88%.
For comparison to Android OS upgrades, only 15% of users were on the latest Android version (Android 12). One can argue that OS upgrades and browser upgrades are very different. OS upgrades have a much more drastic impact on the performance (or non-performance) of a device. Therefore, users are much more hesitant to make the upgrade. Nevertheless, 88% of users on the most recent version of Chrome is very good news for Google.
Eventually, Chrome will “freeze” the user agent-string so that it no longer reflects the state of the device and browser. Instead, Google will rely on the User-Agent Client Hints mechanism to convey pieces of information about the device and browser. It is debatable whether this change is an improvement, but Google has the power to force change, so that ship has sailed.
What if My Home-Grown Detection System is Not Accurate?
If you are in advertising or use device detection in any way, you need to make adjustments to keep your device detection accurate. Hopefully, you already use WURFL device detection, because WURFL has already made changes to integrate User-Agent Client Hints, recognize frozen user-agent strings, and reconcile these two sources to ensure accuracy.
If you have a home-grown system that is suffering from poor accuracy, that is not a surprise. Most user-agent parsers (both home-grown and open source) are inaccurate 22% of the time. Read more about why that accuracy is getting worse. Keeping track of new devices is difficult enough for companies for whom it is not their core mission. JavaScript hacks that do simple UA sniffing are not going to work well going forward. Now that frozen User-Agent Strings and User-Agent Client Hints are complicating matters, home-grown solutions are breaking quickly. Contact us. ScientiaMobile can set you up with a free 30 day trial so you can see the improvements yourself.

Learn more about User-Agent Client Hints
Below is ScientiaMobile’s webinar about User-Agent Client Hints.
We go into detail about:
1:25 What is WURFL (Wireless Universal Resource FiLe)?
2:10 What is Google changing in User-Agent Strings and User-Agent Client Hints?
3:10 WURFL device detection automatically accepts UA Client Hints
3:30 UA Client Hints Timeline and Google
7:15 What to UA Client Hints Do?
10:00 Myths about UA Client Hints
16:20 What Should People do to Implement UA Client Hints?
22:00 How WURFL works with UA Client Hints: