updated 02:35 pm EDT, Mon August 29, 2011
Desktop iCloud betas so far restricted to Lion
Apple may be working on a Mac OS X 10.6.9 update to extend iCloud to Snow Leopard, an error message reveals. After upgrading a MobileMe account to iCloud, one developer says he encountered a unique error message in Tiger's .Mac preferences pane. "You will no longer be able to sync with this machine because you've upgraded to iCloud," it begins. "iCloud requires running Mac OS X Snow Leopard v10.6.9 or later for Contacts, Calendars, and Bookmarks."
The latest version of Snow Leopard is in fact v10.6.8, which implies that the company is working on one final update of the OS, presumably with iCloud support as a primary goal. To date Apple has only released iCloud betas for Lion. The company has in fact stayed relatively quiet on the topic of iCloud requirements, only stating that "some features" of the platform will require Lion, Windows Vista, Windows 7 or iOS 5.
A formal launch date for iCloud hasn't been announced. The platform is closely tied to iOS 5 though, and Apple is expected to announce new iPhones and iPods in September or October, by which time iOS 5 will have to be ready so it can be preloaded.