Hello,
I just downloaded an update through LU 10+ mb and should be the first part of the new version 20.3.0.12.
Two new folders "21.3.0.12" have been added to C:/Program File/Norton Internet Security/ "Engine" + "MUI".
No reboot is required and the version remains unchanged.
At the moment, the update still does not appear on Product Update Announcements which will probably be updated soon.
Sandro