I had 10.13 beta installed and disabled beta updates in App Store settings when 10.13 came out of beta, but I am still receiving notifications to install beta updates and I am also receiving daily notifications to "Get to know your mac" and they won't stop no matter what I click.
With the App Store closed, run this command in the Terminal.
sudo softwareupdate --clear-catalog
I have tried that command before and it says "Changed catalog to Apple production" but it does not work. Software update itself doesn't show any beta updates, the notifications just keep appearing.
What version of High Sierra are you running?
10.13.1 beta 17B35a
I wou;d try installing the release version from the app store. It's newer than what you have. The betas are up to 10.13.2.
