This is a great website to read just to know what could be wrong with Mojave after you have updated to it, and what you can do to fix what’s broken.
https://blog.macsales.com/46143-macos-101-what-mojave-broke-and-how-to-fix-it
Here are the things that are covered:
- SMS Messages (to non-Apple devices) not delivered 
- Weird fonts 
- Bluetooth devices not connecting to your Mac 
- Freeze or slowdown at login 
- Apps no longer working 
- Apps and security changes in Mojave 
- 32-bit apps and other non-working software 
John R Carter Sr
