Aperture was first released by Apple in 2005 and then discontinued in 2015. Its features were integrated into iPhoto. If still using Aperture, you will need to migrate your photo collection to another photo app before uploading them to FOREVER®. You can migrate them to the Photos app, which is included with macOS Yosemite or later, or migrate them to Adobe Lightroom Classic or another app. You should do this before upgrading to macOS Catalina.
Follow this link, to migrate your Aperture Library to another Apple Photos app. https://support.apple.com/en-us/HT209594 Once in a modern photo application, you’ll be able to download to your computer and then upload into FOREVER®.