This one has taken us by surprise - the Fitbit Blaze is capable of receiving WhatsApp messages... at least when paired with Android smartphones.
Within the Android Fitbit app there is an option to turn on notifications for WhatsApp, Skype and Google Hangout messages within the 'Text notifications' settings screen.
We've tested them out and they all work fine - although Skype messages are a bit hit and miss (but, let's face it, Skype on the whole is hit and miss).
Now, this is news to us and seemingly news to Fitbit as well. For notifications, the official specs list only native notifications from your phone like calls, texts and calendar alerts.
We even quizzed Gareth Jones, vice president and general manager for the Fitbit EMEA division about the lack of third party support when we spoke to him last week.
"We've got a product that delivers texts, calls and calendar notifications. That's what people want when they're on the treadmill. Now they've got that, people are saying that they want things like WhatsApp support," he told us.
"Right now the product doesn't have it, but that doesn't mean were not listening to what people want. It's on that list of 'we know people want this' and we will look at the viability to it."
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It looks as if Fitbit may have slipped the update out quietly; the latest version of the Fitbit Android app hit Google Play last week.
The UI is a bit clunky in the settings however, and you can only select one third party app to be 'on' at a time. Could Fitbit have accidentally put live a feature it hasn't fully developed yet?
We've asked the company for comment and we'll update the story when we hear back.
But for now, at least, third party notifications are possible on the Blaze - and that's a nice bonus.