Ubuntu upgrade path from 14LTS to 16.04 LTS

The upgrade on a laptop took about 1.25 hours. It consists of a 1200 file download (could vary depending upon what you have loaded), followed by an installation of those downloaded files, and a cleanup. There is a Q&A regarding UFEI so you can't just start it and walk away. Over all it was a clean install. I did back up to an external USB some "custom" files I had. There were two occasions where the screen dimmed - the first was longer than the 2nd but the install continued w/o incident. Email, bookmarks and the like remained in effect.

[EDIT] I should point out that I do not crunch on this laptop. There have been some concerns with drivers and AMD with Ubu 16 so proceed accordingly. The UFEI option to enable/disable had something to do with 3rd party drivers but I did not pursue it at this time since I do not crunch on this laptop.