Meryl Baer, blogging at Six Decades and Counting, describes her frustrations trying to prepare her taxes. In order to use Turbo Tax, she had to upgrade her OS, operating system.
That happened to me several years ago. I was stunned after buying Turbo Tax at Costco that it wouldn’t work on the OS I had on my Apple computer, Snow Leopard. I couldn’t update to El Capitan quickly because I had 100,000 photos on my computer’s hard drive. I had to figure out to get the photos on an external hard drive first.