EPUB files are not syncing through iCloud for iBooks along with iOS 9.3 Since 21 March 2016, I am able to sync any books via icloud between devices. It works pretty good for pdf. But it doesnt work for EPUB files. I have downloaded for my iPhone some EPUB file from the website and saved to iBooks, but it didn't appear on my another device, while the pdf did appear. 

What is wrong?
In iOS iBooks try tapping the "Collections" selector top center of the app below the system time and turning OFF "Hide iCloud Books".