Samsung is trying to release Android 13 and One UI 5.0 as soon as possible. However, this has come at the expense of security code updates, with Samsung needing much more time than usual to release the updated security code version for November 2022.
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The Galaxy S21 series is an example of how the Android 13 update didn't come with the latest security patch — the update was released with the October security patch in most countries. But now Samsung is bringing the November security patch to the Galaxy S21, S21+, and S21 Ultra via what's called the "Galaxy 21 series update 2.0" that's based on Android 13.
A new update is released for the Galaxy S21 series (excluding the Galaxy S21 FE, which received the November 2022 code update less than a week ago) in about twelve European markets. It comes with firmware version G99xBXXS5DVK1 and includes the updated November 2022 security patch version.
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The new update is purely focused on strengthening device security, which means that any glitches you experienced with the initial Android 13 build for the Galaxy S21 series likely won't be fixed with this new software update. In Samsung's defense, however, the Android 13/ One UI 5.0 update has been pretty stable for most flagships that have received it, so most users shouldn't have any reason to complain .

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You can download the November security update for your Galaxy S21 series smartphone from the Settings » Software update using the Download and install.
Information source: sammobile.com
