Reverted back to Mavericks, can't use some apps now

I started having GPU problems when I updated to Yosemite on my early 2011 15" Macbook Pro in November. When I updated to the most recent version last week, my Macbook bricked on me. The computer repair guy was able to get my computer to work with Mavericks, but now I can't use many of my apps. I had a back up copy of the apps, but many of them were updated since November. I get the following message: "You have OS*X 10.9.5. The application requires OS*X 10.10 or later"
Is there any way of getting older versions of the apps that would work with Mavericks?
Thanks

You may be able to get hold of older versions that will work with Mavericks but that's up to you to find out by going to the developer's site and check. It would be much easier if you just reinstalled Yosemite. There's no reason why a 2011 15" MacBook Pro can't run Yosemite better than Mavericks.