HTC has been terribly vague about which devices will get Ice Cream Sandwich, the next major version of Android, as they are with almost any Android release. However, today they have announced via a brief Facebook post which devices will get the update. Hint: it's not many.
According to the post, the HTC Sensation, HTC Sensation XL, HTC Sensation XE, HTC Rezound (US only), HTC EVO 3D, HTC EVO Design 4G (US Only) and HTC Amaze (US Only) will get the updates. This means that only devices from 2011 will see the update right now, and many others will likely be left to their own methods.
The announcement follows typical behavior by Android vendors; only updating extremely recent devices to the latest version of Android, and leaving the rest of their user base to find their own way to upgrade. The practice can leave users open to all sorts of bad things, such as phishing attacks from 3rd party ROM's or bricking their phones.
They did at least say that they're "continuing to assess [their] product portfolio" for device upgrade timing, however this is usually corporate speak for "it's not likely that older devices will see the updates officially."
But hey, it's good to see HTC try, right? The updates won't begin until 2012.