Does it mean that version 12.7 no longer supports Window and you either do not update iTunes or have to sync your books from iPhone to iPad from now onwards? I heard you can switch it back to the classic mode but could not find it in the menu.
The latest version of iTunes 12.7 for the Mac does not include iBooks. I would imagine it also has been removed from the Windows version. However, macOS includes an iBooks application whereas there isn't one for Windows.
If you still have your older version of iTunes installed (12.6), I would leave that in place for now and not upgrade. Otherwise, in order to get the same book on an iPad that you have on your Windows PC or iPhone, you will have to go to your purchased items in the iBook store and download it again. Probably a real PITA.
Personally, I do not use iBooks at all and get all my books using the Kindle. Kindle has an app for iOS, Windows, Mac, and Android. Once you purchase a Kindle book from Amazon, you can download it and read it on any device you own.
BTW, the forum software will not allow me to give my opinion of this newer version of iTunes.
