Just to add some words about my 'User experience' to this:
My nagging screens started the day the 'Update service' expired (in the begining of december 2020). I never got a "Don't show again" check box. Clicked them away for months, hoping to get a check box when a new version is released.
That hope vanished in march.
Then pulled the plug by blocking Xara with the Windows firewall as one of you nice guys recommended.
No nags since then.
Can't insert 'Font awesome' symbols anymore (along with anything else from the online content catalogue), but "SO WHAT"!