Mac OS X 10.15 Catalina was released on October 7, 2019.  This new Mac operating system requires applications to be 64-bit compliant. 

ColorMunki Smile software is a 32-bit application, and will not run on Mac OS X 10.15 Catalina. 

There are no plans to develop a 64-bit application for ColorMunki Smile. 

The i1Display Studio and i1Display Pro devices have 64-bit applications that will run on Mac OS X 10.15 Catalina. 

To continue to use the ColorMunki Smile on a Mac, you will need to avoid upgrading to Mac OS X 10.15 Catalina. 

If you decide to upgrade to Mac OS X 10.15 Catalina, you should consider upgrading to the i1Display Studio or i1Display Pro.