HTC has worked parallel on two projects: HTC Sense 4.0 and HTC Sense 3.6. The difference between the two is not going to be that significant, but most likely the Sense 3.6 UI will be used for the update for the current models, coming as a light version of the Sense 4.0 UI boarding to the HTC One X series.
One of the lineups which will receive HTC Sense 3.6 will be the HTC Sensation series. The HTC Sensation XE, which sports appealing features even without the Android 4.0 ICS update, will be using Sense 3.6 making only some features of the ICS available for the handset. With the current update the HTC Sensation XE will be able to use the four customizable icons and stackable apps for folder creation.
The official statement from HTC representatives is the following:
“HTC Sense brings a variety of new software enhancements to HTC One, some of which utilize the latest hardware innovations, meaning not all functionality can be introduced to older HTC Devices. With that said, we are looking to bring a Sense 4 software update that includes as many of the enhancements as possible to a variety of our new devices.”