Syncing Contacts to iOS on Mac OS X 10.6 What is the oldest Mac OS version that can do iCloud sync from Contacts/Address Book to a current iOS 9 device (iPhone SE, in this case)? The goal is to sync contacts between my Macbook running OS X 10.6 and my iPhone.

If iCloud sync is not possible, what synchronization options in 10.6 would allow for contact synchronization to current iOS?
According to http://www.apple.com/icloud/setup/mac.html iCloud requires 10.7.5 or later. 

Since iCloud encrypts data between the client and the server, you won't find third party options. I would get whatever software you need on 10.6 upgraded and then upgrade the OS or set up virtualization to run 10.6 from within a newer OS if iCloud data sync is needed. 

Perhaps you could find a different cloud sync between to that's likely more work and aisle than the above.