HTC has confirmed plans to release Ice Cream Sandwich (Android 4.0) for a number of its smartphones -- 16 to be exact. One thing all of the phones seem to have in common is they were released in 2011. If you have a handset dating back to 2010 or prior, then you may be out of luck for any future update to ICS.
If you can navigate past HTC's bad Ice Cream Sandwich puns, the blog lists what smartphone models can expect to see ICS. With sticky, sandwich cookie-crusted fingers, HTC points out the following devices (alphabetical order): the Amaze 4G, Desire S, Desire HD, Droid Incredible 2, Evo 3D, Evo Design 4G, Incredible S, Sensation, Sensation 4G, Sensation XE, Sensation XL, Raider, Rezound, Rhyme, Thunderbolt and Vivid.
The blog post mentions that upgrades for the Sensation and Sensation XE will be "more widely available" in the next few weeks, which suggests that some updates may already be trickling out. The handset maker also mentions that the Sensation 4G and the XL will follow next but after that, any sort of release schedule remains a mystery.
It's worth noting that even though HTC may release an update tomorrow, it could take months for carriers to release that update to contract phone users. As a result, HTC claims they are working closely with carriers to pin down release dates and update schedules. Hopefully they'll release more information as the specifics come to light.