Realme released the November 2021 security update for the Realme C21 smartphone via OTA. Recently Realme C21 received its first android update i.e android 11 with UI customization options, a new fun design, three-style dark mode, notification history, and more.
Realme C21 is released in March 2021 with android 10 out-of-the-box.
This device already got September 2021 Security Patch with C.03 Build recently, but again comes with stability improvement.

Source: Realme community
| Android OS | Update | Released date/status |
| Android 10 | Out-of-the-box | March 2021 |
| Android 11 | First OS update | September 2021 |
| Android 12 | Second/last Os update | Eligible/unconfirmed |
The Android 11 Update is its first major OS update which was released in September 2021 And, it is eligible for the upcoming Android 12 update too.
The Android 12 update will most probably be the last major OS update for it. But, it is still unconfirmed.
For more Realme updates please download our android app – Available on Play Store