I have the updates set up to notify me when available, so a rectangle window pops up and I click download update.  But for the last week or two, another update window is popping up as well.   It's different and maybe a bit smaller and says "Update for full protection. Update now to make sure your'e runing the best of the best.  You might need to restart your pc."   And there's a button to click, which I do.

So why this new window is popping up?   And is it a different update than the one I always got (and still get)?

Thanks.