How do I upgrade from 10.8 to 10.11
I need to upgrade to use some applications that do not work in Mountain Lion. When I go to the download at the App store it is telling me that El Capitan cannot be install on my computer. (Sierra is too new, afraid of incompatability) I have a late model 2012 iMac. It should work. Unless I have to upgrade one at a time. Like 10.8 to 10.9 to 10.10 etc. Am I under a delusion when I say that i think these are all free downloads? What could be the problem?
iMac, OS X Mountain Lion (10.8.5)