pop ups unwanted

I cannot install anything past Yosemite 10.10.6, yet Adobe has been inserting a notice every 5 minutes onto my desktop screen telling me to upgrade when no download is available for my old system. 

I am trrorized by this bullying any time I go on my old mac which I require to run large format Epson printers for which no current  computers have the dedicted Priter Drivers which I rely on .

I use photoshop to manipulate the images which we enlarge and print on 44ich canvas.

I also use newer iMacs to run all the new Creative Cloud programs. Despitr that I am harassed on the old er desktops by thies horrible pop-ups litterally every 2-3 minutes