Merlinos Mills is a company that produces flours and grains for grocery stores. It owns mills and distribution centers in the Northwestern and Midwestern United States. The headquarters in Bend, Oregon employs more than 400 people, most of whom use computers. Also, the headquarters has 28 servers, all running Microsoft Windows Server 2012 R2 Standard Edition. The company employees use Windows 7, Windows 8.1, and Mac OS X El Capitan. The management of Merlinos Mills wants each department to upgrade to newer OSs. Also, they are very concerned about network security, and they want to install new servers and upgrade their current servers to OS versions that take better advantage of security features. Your role in the process is to work with each department to help ensure that the installations and upgrades go smoothly.

The Marketing department only uses computers that run Mac OS X El Capitan and is planning to upgrade to macOS Mojave. What steps should it follow for the upgrade?