how can I update my software

FWIW, You don't have to update your 32bit software unless you are planning on upgrading to Catalina. However, if you are and there are no 64bit drivers for your printers, yes, they would have to be replaced.

You're welcome. FWIW, it will be possible to keep Mojave or whatever version of macOS you are currently using and install Catalina on a separate volume or partition.