MacOS 10.14 Mojave, the version of the Mac operating system before the new macOS Catalina, is the last version that supports 32-bit software. With Catalina, only 64-bit software will be supported.
Catalina is here and if you decide to upgrade to the new macOS, you need to do a bit more than usual to prepare your Mac. You need to make sure your apps are 64-bit versions. If your app is a 32-bit version, it will not work.
AppleApple actually started to warn people about the change with macOS 10.13 High Sierra. If you launch a 32-bit app in High Sierra, an alert pops up to tell you that your app needs to be updated. The alert appears only once in High Sierra, and in Mojave, it appears every 30 days.
