Mac Pro introduced in 2013, plus mid-2010 or mid-2012 models with a recommended Metal-capable graphics card.
Your Mac also needs at least 2GB of memory and 12.5GB of available storage space, or up to 18.5GB of storage space when upgrading from OS X Yosemite or earlier. You can upgrade to macOS Mojave from OS X Mountain Lion or later on any of the following Mac models.