12.8 update not permanent (W10 Pro Build 1803)

Got notification of 12.8 update and proceeded to download and install, Rebooted and checked to verify installation OK. 12.7 still current despite DOpus having said 12.8 download and installation successful. Repeated with same result! Guidance required please.

My guess is that your antivirus is blocking the new files from being written.

The first thing I'd try is downloading the installer from here and running it manually. The a/v may treat it differently.

If that fails, try disabling the a/v scanner and/or checking its logs for anything being blocked.

Reboot if prompted at the end of each install.

Thank you for prompt response. Tried all your suggestions but no joy. Have currently bypassed the problem by uninstalling 12.7,rebooting and then downloading and successfully installing 12.9. Will look forward to next update to see what happens.