Although Apple’s Aperture photo editing software has been pretty much unsupported and dead since 2014, there are still people who still choose to use it. Forcing peoples hands, though, Apple pretty much put the final nail in the coffin with the latest macOS Catalina by refusing to even run it. Catalina also made it no longer possible to use iPhoto app (also discontinued).
The reason for their final demise was that Catalina is now a 100% 64-Bit OS, although those are 32-Bit apps. Now, though, programmer Tyshawn Cormier has pulled out the claw hammer and removed that nail with a new app called Retroactive that lets you use both of these applications under the Catalina operating system.