What a surprise. Just got back my HTC One (M7) back from HTC service center today and I received the notification to update to HTC Sense 6.0 and the latest software version 5.12.707.3. Some might have already upgraded their handsets since HTC started to roll out worldwide.
Basically, after the upgrade, the UI feels the same as HTC One (M8) since they have the same UI version. It also comes with the Extreme Power Saving Mode, color coded themes, new interface for Gallery, new Blinkfeed and etc.
If you have not received the notification, go to Settings and check for software updates. Have fun with the new Sense 6.0