Samsung has started sending out the May 2025 security patch to Galaxy S21 phones in Asia, with Vietnam getting it first. The update helps fix security issues and makes more stable. This comes as Galaxy S21/ S21+ and S21 Ultra wraps up their major Android update cycle.
The file is about 300 MB and s fast. It may take hours or days to reach every phone, this is a phased roll out by Samsung.
What’s in the update
- Improved security and stability
- The patch fixes many security loopholes and makes the system run more smoothly.
First Android 15-based patch
This is the first security patch on Android 15 and One UI 7. It also brings minor bug fixes and small performance gains.
Also Read: These Samsung Galaxy phones will miss One UI 8
Availability and build numbers
| Model | Build version |
|---|---|
| Galaxy S21 | G991BXXSFHYE1 |
| Galaxy S21 Plus | G996BXXSFHYE1 |
| Galaxy S21 Ultra | G998BXXSFHYE1 |
How to install
Go to Settings > Software update > and install. Manually checking can help you get the patch sooner.
End of major updates
This marks the end of four major Android OS updates for the Galaxy S21 line. These phones started on Android 11 and now run Android 15. They will get security fixes for one more year but will not move to Android 16. The Galaxy S21 FE will get Android 16 with One UI 8 later.
Tip: Install the update as soon as it appears to keep your phone safe and smooth.
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