The Mac I'm purchasing is running a patched version of MacOS. This patched version is a modified install of a more current offical MacOS than is natively supported on the Mac that I'm purchasing. The purpose of the patch is to extend the life of the Machine by giving it important security that will allow it to connect to websites for many years.
The patched OS is great for many activities such as email, websurfing, creating home use content, watching movies and more. However we don't recommend running a patched OS for production, such a s professional use of applications like Adobe Creative Suite, Photoshop, Logic, Aprature, Serato, etc. Many of these apps will run with no issue but there is no way to gaurantee 100% support.
Performance of third party is not guaranteed. Machine can be reverted back to a native macOS at no cost.