Android Wear

Apple Watch was the leading smartwatch in the second quarter, with an estimated 4 million shipped worldwide, for a market share of more than 75 percent, according to Strategy Analytics. Samsung was a distant second with 400,000 shipped and a 7.5 percent market share.

However, the market is still nascent, and Apple Watch isn't an option for people who use Android smartphones.

Samsung's Gear S2 will work on Android - and for the first time, not just Samsung's Android phones. Meanwhile, watches running Google's Android Wear software will now work with Apple's iPhones.

The new Outlook app is exclusive to the Apple Watch, allowing users to read full emails on their wrist and send pre-written or dictated responses.

Updated versions of OneNote and OneDrive have landed on Android Wear. The cloud-storage service will now use recently-uploaded photos as a watch face each time the device is activated.

Translator is available for both platforms, enabling users to convert spoken English into 50 different languages and save their favourite translations for quick reference.