Please make sure you don't upgrade to macOS Catalina, Big Sur or any newer version, as Solar Eclipse Maestro, Lunar Eclipse Maestro and Mercury Venus Transit Maestro will not be compatible. It's recommended you stay on Mojave for the time being.
If you still choose to upgrade then the only way to run SEM, LEM or MVTM will be to do so using a virtual machine (VM) running with the help of Parallels Desktop, VMWare or VirtualBox (free).
A complete rewrite of the three applications will be necessary to move from the 32-bit Carbon framework to a 64-bit one and unfortunately this may take a couple years to achieve. In that regard your support is important and a donation would certainly help in the process.