I just received this. Existing software on your system loaded a system extension signed by “Malwarebytes Corporation” which will be incompatible with a future version of macOS. Contact the developer for support. What is a good option for Malewareby

You have a 32-bit, older version of MB. If you upgrade to Catalina or later, then you will need to get the current, 64-bit version. Your older version will no longer work after upgrading from Mojave.

The next major release of macOS will not allow third party kernel extensions. It's just warning that any third party software you're using that installs such extensions will not work in 10.16.

All vendors who now user kernel extensions will have to use a different method to load items at startup.

See: About legacy system extensions - Apple Support

FWIW, Kurt was actually correct.

I have this message too, and have 64 bit Catalina.

So your answer is not necessarily fully correct.