OS Version

OS version is the exact build of a user's operating system — Android 14 versus Android 9 — one level finer than the OS itself.

Just as a technical decision is made on the browser version rather than the brand, here it is the OS version that determines real behavior, because security capabilities, support for new formats and default-browser behavior all depend on the build. The value of this data is in finding the tail: a group stuck on a build several years old may not see a feature or may have an insecure experience while being lost in the headline OS numbers. But two points: first, the old-version tail is longer in markets with cheaper devices, so a global pattern cannot be assumed; second, the User Agent string does not always give the exact version and part of it falls into an unspecified bucket. Read the OS version for support and security decisions, not to identify a user.