The big "problem" for me with Catalina is its loss of support for 32-bit addressing. And with Mojave I'm happy to be able to use a number of 32-bit applications that have no 64-bit "upgrade", including the TexEdit text processor that rulnacco mentioned just above. I'll continue to review my software in view of available 64-bit versions. Should I fear being an old fogy stuck in the past? 🙂