Continuity and Handoff
Continuity is Apple’s umbrella term for a number of features in Yosemite, all of which make it easier to share stuff between your Mac and iOS devices.
Perhaps the most exciting element is Handoff. This is a feature that allows you to start working (when writing an email, for instance) in the Mail app on your Mac and continue it on your iPad or iPhone. You can do this without having to save the work first or figure out how to move it from one device to another.
Whenever you have a Handoff-compatible app running on your iPad or iPhone, and it’s close by, the app’s icon appears to the left of the Mac’s Dock. The other way around, the icon of the Mac app appears on the iOS device’s Lock screen and at the very left-hand side of the app switcher. Click on the icon on your Mac and it opens the equivalent application, complete with the document you were working on on your iPhone or iPad. On the iOS device, tap the icon and it opens the iOS app with the document ready for you.
Continuity also includes the features in Messages that allow you to send and receive SMS messages, and in FaceTime, where you can make and receive phone calls from your Mac.
For these to work your iPhone needs to be close by and connected to the same Wi-Fi network in the first place. Take note that you’ll need to upgrade your iPhone to iOS 8.1 to use the SMS relay in Messages.
iOS 8.1 with Yosemite also allows you to use your iPhone as a Wi-Fi hotspot for your Mac, although your mobile network dictates whether this feature is allowed.
The third element of Continuity is AirDrop. Previously it was only possible to AirDrop files between Macs or between iOS devices, now you can go one further and share them from Mac to iOS device or vice versa.
Continuity pulls some clever behind-thescenes tricks using Bluetooth 4 and Wi-Fi, but this means it won’t work on every Mac that runs Yosemite. You’ll need a Mac with Bluetooth 4 (which means anything released before the MacBook Air mid-2011 won’t work). The MacBook Air mid-2011 and Mac mini mid-2011 both have Bluetooth 4, but the iMac and MacBook Pro didn’t get it until 2012.