Good news for iPhone 5, 5c, and 5s owners: You don't need a 6 or 6 Plus to use Apple Pay on the watch. iOS 8.2 just put the Apple Watch companion app on every compatible iPhone, which is where you'll add your credit or debit card information to store in Passbook. No financial details are stored on the watch itself, but the device does store a token, or a number to act in place of your card number, so you don't need your iPhone with you to use Apple Pay.
The iPhone 6 models have a dedicated "Secure Element" chip that stores your encrypted information--not your actual credit card numbers, but rather a "device account number" that is used to create a single-use security code to authorize each transaction. The phone provides the watch with information about the items stored in its own Secure Element, and then the watch has the ability to use those items itself in order to pay wirelessly. There's a nice security touch, too: If you take the Apple Watch off, it'll lock and require a code before you can purchase anything, so if someone steals your watch they won't be able to use it as a credit card.
What kind of apps did Apple build for Apple Watch? Will it run third-party apps? Apple went all out for the watch, building in many of the common apps that we use every day: Messages, Mail, Weather, Calendar, Maps, Passbook, Music, Photos, and more. A few notable omissions: While the Apple Watch can act as a viewfinder for your iPhone's camera, letting you snap pictures and even set the self-timer, it doesn't have its own built-in camera. Nor does it have Safari, Apple's Web browser--all the information you get is mediated through those apps.
Still, if what Apple builds into the Watch isn't enough for you, the company is supporting third-party apps and Glances off the bat. We've seen glimpses of how must-have apps like Instagram, Uber, and Twitter will work at launch, and a list of high-profile app partners is here. Indie iOS developers have been able to tap into the WatchKit SDK, which Apple introduced in November, to build their own apps. They shared with us some of their experiences building apps for a device they hadn't seen in person yet.
What kind of battery life will the Watch have? Apple says the Watch will have all-day battery life, which means up to 18 hours of active and passive use: 90 time checks, 90 notifications, 45 minutes of nonstop app use, and a 30-minute workout with Bluetooth music playback from the watch, which can store up to 2GB of music locally. If you've been a bit overzealous in your watch usage and your battery starts to dwindle halfway through the day, the watch will automatically default to a Power Reserve mode for up to 72 hours so you'll still be able to see the time (but not anything else). Basically, if you plan to buy an Apple Watch, expect to charge it next to your iPhone every night. Apple did say that the watch battery will be replaceable, but didn't give details as to how much replacement batteries will cost.
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