How can I upgrade High Sierra to Mojave or Catalina?
My 2017 iMacPro is running OS10.13.6. Haven't upgraded as yet because the system is, after a couple years of problems, stable with critical peripherals.
Now, I am getting occasional msgs that the OS is incompatible with certain products, such as Logic remote. So, I need to upgrade, but I cannot upgrade to OSX11 because several of the critical peripherals I use are not yet compatible with it. So, I need to upgrade to Mojave or Catalina, and can find no way to do this.
On the App Store, I get the message that the files cannot be found. What can I do?
This is a really bad situation in which Apple has again obsoleted a range of products but it seems this time, there is no solution. Can this be true?
-A
iMac Pro, 10.13