(1) Microsoft Office license did not transfer. Ether I had to buy a new version or subscribe to Office 365. I have decided to use Pages, Numbers and Keynote instead.
(2) Final Cut Pro ... It's no longer working on El Capitan OS. I guess I have to start using iMovie.
(3) Apple Aperture does not work anymore. After few days of struggle, I have decided to move to Photos.
In a old days, hardware and software manufacturers are working hard to make sure the new is compatible with the old. But, it is not like that any more. You need to accept the changes and move on to the new (sometime better) solutions. It's a pain but in the long run, you will be happier adopting to the new technologies.
If you do not like the change, you should not upgrade your software especially your OS.