Realme has just begun rolling out September 2021 Security patch for Realme C25 users. This is a regular security patch update, without noticeable improvements in the device.
Realme C25 was released on 27th March,2021 with Android 11 out-of-the-box.
This update brings the September 2021 security patch which was released on 11th October 2021.

Source>> Realme Community
Although, it says the update is being rolled out on October 2021, but it has the previous month security patch.
| Android OS | Update | Release Date/Status | Estimated Months |
| Android 11 | Out-of-the-box | March 2021 | Nil |
| Android 12 | First OS update | expected | unconfirmed |
| Android 13 | Second/Last OS update | – | – |
The Realme C25 came with Android 11 out-of-the-box and it’s anticipated that it will receive an Android 12 update.
Check Out: Realme Android 12 Update list Based on Realme UI 3.0
Hence, for Realme C25 Android 13 Update will be the last major OS update on this device.
The Realme C25 came out with Android 11 with out-of-the-box.
Once the update is available on your device, you can head over to Settings >> About Phone >> Software Update section to update your Realme device with the latest security/software update.
For more Realme Android updates please download our Android App – Available on the Play Store