I welcome you to my article once more my dear friend, knowing how to upgrade from El Capitan to high sierra is important. I will be sharing with you a very little but important secret that will help you in your journey.
I will show you how to how to upgrade to high sierra Mac, how to install high sierra on an older Mac, and a few more. You should be able to upgrade from Yosemite to high sierra through a Mac high sierra download on your Mac.