How can I upgrade from Mojave to Catalina ?

And for added protection on Mission Critical machines >>

Do you have a Rescue Plan In-Place. This comprises having 3 Backups using 2 methods and 1 Off Site incase of Theft, Loss or Natural Disasters. A Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS. For addition purposes - two Tested Bootable Clones each to separate external drives. This is insurance incase the upgrades goes sideways. At least one Tested Clone and / or Time Machine Backup should be Off - Site

Back up your data, check your applications for compatibility, and unless your Mac is a 2010 or 2012 desktop Mac Pro, click on Catalina. If it is, you can't.

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Yes, you should.

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