I'm still running Mac OS 10.11 El Capitan. I've decided to upgrade, but I don't want to lose 32-bit support, so Catalina is not an option for me.
I found this official Apple page: https://support.apple.com/en-us/HT210190
However, the link on that page to download Mojave (https://itunes.apple.com/us/app/macos-mojave/id1398502828?ls=1&mt=12) doesn't work for me. (I have iTunes 12.5.1.21.) It only pops up a message from iTunes:
Item Not Available
The item you've requested is not currently available in the U.S. store.
How can I upgrade to Mojave?
Best Answer
Open the link in Safari so that it finds the Mac App Store to open the application.
If you have failures after getting the Mac App Store to receive the link or the installer is too small or doesn’t work, this post is amazing and can help with different issues specific to machines and OS versions.