Degree of layout/interface changes from 11 to 15?

Trying to help an elderly relative get back into PS Elements after our family replaced her computer. She was running version 11 on Windows 7 and very happy with it. Now she is on Windows 10 with a trial version of 11 and we cannot find her serial number.

Are there dramatic changes in layout/interface between 11 and 15? This would be upsetting for her. I would rather track down a point of purchase for a version 11 serial/key than force her to puzzle out an entirely new layout.

But if version 15 is mostly similar to the layout and menu structure of 11, then we may just purchase the latest. (She is doing extensive genealogy work with many family photos.)