We will often read about macOS Catalina problems in this forum in the coming days. Since I offer apps in the App Store myself, I also had to learn quickly that Catalina places different requirements on our apps than previous macOS systems.
As a beta tester, I was able to gain experience very early with the Xojo 2019 Release 2. Xojo Inc. and we beta testers have worked hard to discover and eliminate as many problems as possible. Shortly after the Catalina release I received first messages from users reporting challenges in Catalina with one of my Apps. Since Final Canditate 1 of Release 2, I've been using it for updates to my App Store Apps and have not received any new issues reporting issues on Catalina since then. So far, only one of my apps has been affected, but I am very happy that Xojo Inc. has responded so quickly and can provide the most important changes for Catalina already 2 days after the release of Catalina.
So a big thank you to everyone at Xojo Inc. for their awesome work and performance. :)