While there is still no official release date for Catalina, macOS 10.15 is coming soon.
There are plenty of new features and enhancements included in Catalina; for more information, check out Apple page: https://www.apple.com/macos/catalina/features/
However, there are also some significant changes coming, including the end of 32-bit applications, and support for 32-bit applications.
This has some wide-ranging implications: applications that have been giving you that annoying pop-up about your app not being optimized for your Mac will go away and you quite simply won’t be able run that application.
It also presents a few challenges for those using virtual machines or emulators (Parallels, VMware Fusion, Wine/Crossover). The team at CodeWeavers have written a great article here explaining their current progress, and the challenges that lie ahead before a solution will be available.
If you haven’t seen the alert above for months, and you are confident that you can survive in an exclusively 64-bit world, upgrade to Catalina as you see fit (making sure to have a good backup with Time Machine, or a image of your Mac with a app like SuperDuper or Carbon Copy Cloner).
However, you are still seeing that alert regularly, or if you know that you use a virtualisation solution, or an emulation solution like Crossover, resist the urge to upgrade and be an early adopter until compatibility with your applications and day-to-day use is confirmed. If in doubt, free feel to get in touch with us.