Client hints overview and FAQ

Client hints are individual pieces of information about a user’s device. They are provided by Chromium browsers such as Google Chrome and Microsoft Edge. For these browsers, client hints will gradually replace the User-Agent as the source of device information. Adobe Analytics will update its device lookup process so that it uses client hints in addition to User-Agent to determine device information.

Google divides User-Agent client hints into two categories: low-entropy and high-entropy hints.

  • Low-entropy hints contain more generic information about devices. These hints are automatically supplied by Chromium browsers.

  • High-entropy hints contain more detailed information. These hints are available only by request. Both AppMeasurement and Web SDK can be configured to request high-entropy hints. By default, both libraries do not request high-entropy hints.

NOTE

Starting in October 2022, new versions of Chromium browsers will start ‘freezing’ the operating system version represented in the User-Agent string. As users upgrade their devices the operating system in the User-Agent will not change. So, over time operating version information as represented in the User-Agent will become less accurate. Operating system version is a high-entropy hint, so to maintain accuracy of operating system version in your reporting it is necessary to configure your collection library to collect these high-entropy hints. Over time other device information of the User-Agent will be frozen, requiring client hints to maintain device reporting accuracy.

Frequently asked questions

 Where can I learn more about client hints?

This Google blog post is a good reference and starting point.

 How do I enable the collection of client hints?

Low-entropy hints are automatically provided by the browser and included in Adobe’s process for deriving device and browser information. Newer versions of AppMeasurement (starting with 2.23.0) and Web SDK (starting with 2.12.0) can be configured to collect high-entropy hints. For both libraries, collection of high-entropy hints is disabled by default.

 How do I capture high-entropy hints?

High-entropy hints can be configured with the Web SDK and AppMeasurement libraries via their respective Tags extensions or directly with the collectHighEntropyUserAgentHints flag.

 Can I choose which high-entropy hints I collect?

Not at this time. You can choose to collect all high-entropy hints or none.

 Will there be any changes to device reporting in Analytics?

The device fields available for reporting will not change. The data captured for those fields may change depending on which field and how you have configured collection for client hints.

 Which Analytics reporting fields are derived from the User-Agent?
 Which Analytics reporting fields are derived from values stored in high-entropy hints?

As of September 2022, Google’s published timeline for “freezing” User-Agent hints indicates the operating system version will stop being updated starting October 2022. When users upgrade their OS, the OS version in the User-Agent will not update. Without high-entropy hints the accuracy of operating system version, which is included in Analytics “Operating System” dimension, will gradually degrade.

Refer to the timeline published by Google to see the timing for freezing of other portions of the User-Agent.

 How will Adobe use client hints to derive device information?

Adobe uses a third-party, Device Atlas, who will use both the client hints and User-Agent to derive device information.

 Which browsers are affected by client hints?

Client hints only apply to Chromium browsers such as Google Chrome and Microsoft Edge. There is no change to data from other browsers or mobile apps.

 **Are client hints supported over insecure connections?

No. Client hints can only be collected through a secure HTTP connection, such as HTTPS.

 Will client hints be available in data sent to AEP and CJA via the Adobe Source Connector?

Adobe plans to include client hints in data via Adobe Source Connector in the first half of 2023.

 How are client hints represented in XDM?

See the schema documentation in Adobe Experience Platform.

 What are the various hint fields? Which ones affect device reporting?

The table below describes the client hints as of September 2022.

Hint Description High or Low Entropy Example
Sec-CH-UA Browser and significant version Low “Google Chrome 84”
Sec-CH-UA-Mobile Mobile device (true or false) Low TRUE
Sec-CH-UA-Platform Operating System/Platform Low “Android”
Sec-CH-UA-Arch Architecture of the site High “arm”
Sec-CH-UA-Bitness Architecture bitnes High “64”
Sec-CH-UA-Full-Version Complete version of the browser High “84.0.4143.2”
Sec-CH-UA-Full-Version-List List of brands with their version High “Not A;Brand”;v=“99”, “Chromium”;v=“98”, “Google Chrome”;v=“98”
Sec-CH-UA-Model Device model High “Pixel 3”
Sec-CH-UA-Platform-Version Operating System/Platform version High “10”
 What portions of the User-Agent are being "frozen" and when?

See the timeline published by Google. This may be subject to change.

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