S21 firmware issues. My phone don't see the new firmware update

[tongax66]

In my S21 5g (SM-G991B/DS) I have the G991BXXU3BUK8 firmware. In sammobile, I saw does exist a few new firmware versions, but when I try to update my firmware using the normal software update from my phone, my phone does't finding it.

Anyone knows if this is a normal behavior or I need to do another thing?

[JIBACROWN]

This is the same thing I'm experiencing on my s21 too, bcos I'm yet to receive android 13 since the day of release and whenever I check for software update on my phone it keep telling me it's up to date and my last security patch is 1st October 2021