M8

The iPhone 6 and iPhone 6 Plus have both brought an abundance of new features to the table. Among them, Apple has squeezed in a new M8 motion coprocessor, an upgrade on last year's M7, which adds a barometer alongside other notable tweaks. Now, a free new app lets you use the barometer to check atmospheric pressure, and although the app is pretty bare-bones at its current duration, it is the only one that currently doesn't cost any money.