If you refuse to update to Mac OS X Lion from Snow Leopard for the time being, you may still be able to take advantage of Apple's iCloud. This news comes from a message that one developer received after he upgraded his MobileMe account to the iCloud but attempted to access it via a machine still running OS X Tiger. The message indicated that the minimum requirement for compatibility with the iCloud is Mac OS X Snow Leopard version 10.6.9.
Even though Mac OS X Lion is now out in full swing, it's expected that Apple will be updating Mac OS X Snow Leopard at least one more time with a 10.6.9 version. And now it looks like the imminent update will also bring iCloud support. Apple, however, has remained quiet about the exact minimum requirements to support iCloud. It has posted only the following:
Some features of iCloud require iOS 5 on iPhone 3GS, iPhone 4, iPod touch (3rd and 4th generation), iPad, or iPad 2, or a Mac computer with OS X Lion or a PC with Windows Vista or Windows 7 (Outlook 2007 or 2010 recommended).
The iCloud feature was first unveiled back at WWDC 2011, after months of speculation. It was said to replace MobileMe and would offer three core services of email, contacts, and calendars along with 5GB of storage space for free. Apple's next-gen mobile platform with iOS 5 will have the iCloud deeply integrated and is expected to launch within the next two months.