Solved! Go to Solution.
@AM69 Further to @Fiona26 's post there may be a prompt or you can check in Settings-Software Update. The update needs to be downloaded and installed as shown here https://www.samsung.com/uk/support/mobile-devices/how-to-update-latest-software-for-your-galaxy-mobi...
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB
One Ui 5.0,Android 13 .