Hello, I have been using 10.9.5. Considering to upgrade to Yosemite. Could you please let me know the following: 1. Does free upgrade to OS X El Capitan requires one to update to Yosemite first? Can I upgrade directly from 10.9.5? 2. Each major update has some compatibility issues. Since Yosemite has been out for awhile, have the issues been resolved? Thanks.