If a leaked picture of the One trio is to be believed, the new HTC One Max phablet might flaunt fingerprint recognition sensor on the back. It can be used for authentication, mobile payment authorizations and so on, while Apple is heavily rumored to include one with the iPhone 5S, too. On the picture we can also see a dock connector or electrical contacts of sorts, so there might be plenty of surprises to look forward to with the One Max, other than the "first HTC phablet" factoid...
Source: http://www.phonearena.com/news/HTC-One-Max-phablet-poses-for-a-family-portrait-flashes-a-fingerprint-sensor_id46542
Source: http://www.phonearena.com/news/HTC-One-Max-phablet-poses-for-a-family-portrait-flashes-a-fingerprint-sensor_id46542