Remove OS build number from user-agent string

The OS build number (for example, “NJH47F” or “OPM4.171019.021.D1” on Android) has been removed from the user-agent identification (User-Agent header and navigator.userAgent) on Android and on iOS. The iOS change follows Safari's implementation and freezes the build number as "15E148" instead of removing it. This will prevent abuses of that information such as exploit targeting and fingerprinting. It'll also bring Chrome closer in line with RFC 7231 section 5.5.3.


Sample user-agent string before the change: "Mozilla/5.0 (Linux; Android 8.1.0; Pixel Build/OPM4.171019.021.D1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.98 Mobile Safari/537.36" The same string with build number removed: "Mozilla/5.0 (Linux; Android 8.1.0; Pixel) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.98 Mobile Safari/537.36"


Working draft or equivalent

Status in Chromium


Enabled by default (tracking bug) in:

  • Chrome for Android release 70
  • Chrome for iOS release 69

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Shipped
  • Shipped
  • Shipped
  • No signals


Last updated on 2018-08-31