On the larger iPhone it would be handy to be able to see the Notes Side Panel when the device is in Landscape orientation. The Side Panel can be shown / hidden using a swipe gesture. So if the Panel is not showing in Landscape, then swipe in from the right side of the screen and the Side Panel will display. Swipe right to hide the panel. This is now supported in the Chapter Window only. Screenshot of Side Panel for Matthew 24:14 on the iPhone 6S Plus, Chapter Window, Landscape orientation...
Screenshots of the iPhone 6S Plus in landscape orientation - both the main window and the chapter window...
Improved this further - instead of showing "Chapter 13" in the title of the Side Panel it now shows the Book name. e.g. "Hebrews 13". Much better especially on the iPhone Plus when in the optimised landscape view and the book name is not showing anywhere else...