I’ve only known XBMC / Kodi since the open source media center started to show up on ARM based Android and Linux mini PCs around the mid of 2012, and in most devices the default skin called Confluence was used with Kodi/XBMC. It has been used as the default since 2009, and Kodi developers have decided a refresh would be good for Kodi 17 Krypton which will feature two new skins: Estuary for media players and HTPCs, and Estouchy for devices with a touchscreen such as smartphones and tablets.
Estuary does away with the horizontal menu found in Confluence, and instead moves the main menu options to the left. Several widgets have also been added for movies and TV including Random, Recently added, In progress and, Random, and similar options are available for Music too.
The media library has also changed the way it displays movies and TV show information, and if the default color is not your preferred choice, you’ll be able to easily change the background color to orange, green, gray, etc… Find out more about Estruary in the trailer video.
Estouchy looks quite similar, but designed for touchscreens, and with a little less features due to the smaller screen size.