A few days ago I upgraded from macOS Mojave to macOS Catalina 10.15.2. From download to completed install took one hour with out any problems. Tested all my applications and all are working fine. My main concern with Catalina was if my HP Officejet Pro 8625 printer / scanner was going to work correctly. Tested the Printer / Scanner all is well. Catalina is working very fast, faster than Mojave was on my Mac computer. I had my doubts about upgrading to Catalina because of all the reviews and posts on some of the Mac forums with all the problems members were having. I took a chance and upgraded and I'm very satisfied I did.