So I just upgraded, and I'm happy to report that the process went smoothly, no problems so I'm happy about that
I'm also very happy to finally have Ctrl-Y working correctly again...
Just one small problem, every time I open the program there is a blank space at the top between the toolbars and the tree/notes. If I move any of the toolbars then the blank space disappears. I also found other ways to make the blank space disappear : if I double-click the tree header and then double-click it again to dock it, then the space is gone... Also if I minimize Notebook to the system tray, then click the system tray icon to restore the window, the space is gone. But when I exit the Notebook application completely, and then later open it again, the blank space is back every time.
Have you seen this problem? Here is a screenshot :