Microsoft today made the first major update to its Band fitness device since it launched in the US (and, still, only the US) just under four months ago. Today's update touches all aspects of the Band's ecosystem, with new capabilities on the device itself, an SDK to let third-party phone apps communicate with the Band, and a new Web dashboard.

On the Band there's a new Bike Tile, used to track both indoor and outdoor riding. It'll do the expected health band things: GPS will let you map out your rides (including elevation tracking), the heartrate monitor will assess how hard you're working, and so on. The Guided Workout functionality has been updated to include bike workouts.

The Band also picks up some new ways to read and respond to messages. Quick Read shows e-mail, SMS, and other notifications in a large font to let Band wearers read their notifications while in motion without having to scroll.

For replying to messages there is, remarkably, a new virtual keyboard. Although the Band's screen is pretty tiny, the latest firmware adds a miniature keyboard which the company says will enable SMS replies "with minimal errors."

If you don't want to type, you can instead dictate, using Cortana for speech-to-text.

On the Web, there's a thing called the Microsoft Health Web Dashboard providing an online counterpart to the on-phone app. With this, progress toward fitness goals can be tracked, and valuable insights of some kind are offered.

The SDK is currently available for Windows Phone and Android, with iOS coming soon. The SDK doesn't let developers create apps that run on the band itself. Apps run on the phone that's paired to the Band, with the band itself being used only as a source of sensor data (or most of it; GPS doesn't appear to be available) and a place to display notifications and messages.

The concept looks extremely regimented. Developers can create their own tile with an icon or, optionally, an icon plus an unread count, and tapping on the tile can show up to eight stored messages that are laid out in a standard way.