Looks like the news is true - here's an article from Germany's computer magazine c't: CLICK
Sorry, they don't have an english version, but you can follow the links in the article.
A rough summary:
the link from the OP is mentioned and they say HTC announced to update Desire HD, Desire S and Incredible S in April without naming a specific date. The go on mentioning a press release from HTC Netherlands which promises an update to ICS + Sense 3.5 in February for Sensation, Sensation XE and Sensation XL