That's what it says, when I for example start Numbers, Pages, Keynote or any other apps that use iCloud for synchronization. I for example use "Day One" as a tool to write a diary. It states the same there too, and when I update "Day One" on my iPhone IOS7 it actually doesn't sync with my Yosemite computer DayOne version. My Problem: I myself can't update my iPhone to iOS 8 for the reason that my weird Japanese phone Data Plan does not work with iOS 8 Beta. So now I have two different data sync's on computer and iPhone. (I know I shouldn't use a computer I actually use everyday with a beta version of an OS, but I just like having Yosemite and I can live with the small "troubles" there are in a Beta version) My Question now: Should I do my DayOne entries only on my iPhone, or only on my Yosemite computer? When I update iOS7 later to iOS8, which data will be "dominant"? Is there a chance I lose my data that I get's synced to the "iCloud Beta"? Or will I have the choice to choose? What do you guys think? Does anyone know what happens with that "Beta iCloud" data? Thanks!