HTC Desire HD is getting a small firmware update as we speak. This “after Gingerbread” firmware changes are said to bring “Wi-Fi performance improvements” though we guess some other things under the hood will be impacted as well. After all, 19.8MB is kinda big download for such a minor improvement (at least the way I see it). Either way, we’ve no idea what’s all included here, but we do suggest you to “push the button” nevertheless and bring your Desire HD’s firmware version to 2.50.405.2. It’s a good practice to have the latest software running on your phone and I don’t see why this should be an exception.
Still this (because it’s a small update) doesn’t mean you shouldn’t backup first. Something could always go wrong preventing you from accessing the most important information like calendars and contacts.
Finally, as far as we know this is an update for the unlocked HTC Desire HD only and may be released for carrier-branded versions later in the year.