Running 64bit Windows 10 Home with two users, A & B
Installed KIS 21.1.15.500.
Recently when user A logged-in the version self updated to 21.2.16.590(b)
At bottom left of main screen there are two icons Gear Wheel (Settings) and Head (Support).

User B logged in and their version of KIS also self updated to 21.2.16.590(b)
HOWEVER for user B, bottom left of main screen there are three icons Envelope, Gear Wheel and Head.
Removing the ticks from all the boxes in Settings >Interface > Notifications and News Notifications fails to make any change to the bottom left of main screen for user B. The envelope remains and its actions  are unchanged.
I'm prepared to edit the registry - please, just tell me where to make the required change.

Think I’ve found the answer to my own question!!😀

By using Settings  >   Protection  >  Data Provision Agreement  >  Switching off  “Statement Regarding Data Processing For Marketing Purposes”

As well as removing ticks from “News Notifications” and “Promotional Materials” within Settings  > Interface.

Now no Envelope on the Main Screen at thee bottom left side - hooray!!