Current releases of Moving Light Assistant (up to version 1.3.2) are not compatible for the upcoming macOS Catalina (10.15) update. Moving Light Assistant is currently a 32 bit application. 32 bit applications are not supported on macOS Catalina. Moving Light Assistant version 1.4 (when it is released) will be a 64 bit application and will be compatible. Hopefully MLA v1.4 will be available when macOS Catalina is shipped (or soon after). Please keep this in mind when you decide to upgrade your computer to the latest operating system. There may well be many applications you currently use that will be affected by this macOS update.