Buried in its HTC One X announcement, AT&T had said back at MWC that it'd be rolling out an Android 4.0 upgrade for the Vivid — one of the carrier's first LTE handsets released late last year. AT&T doesn't yet appear to be actively pushing the upgrade down to Vivids yet, but it is available; owners can dial *#*#682#*#* to force the download.
We've verified that the technique works on our own Vivid today. The upgrade package is 314.09MB and downloaded very slowly over our typically fast Wi-Fi — it's difficult to imagine that tens of thousands of Vivid owners are hammering HTC's servers to grab this update right now, but you never know. Once the package had completely transferred, the actual upgrade process took 13 minutes, involving a number of restarts, before we were back into a usable phone.
At a glance, this appears to be a worthwhile update for every Vivid owner out there — even though it's not loaded with the more thoroughly revamped Sense 4.0 that'll be available on the One series, HTC has made a few surgical efforts to tone down the skin. The home screen dock is now fully configurable with your own apps, AT&T's built-in apps can be "disabled" (not uninstalled entirely, but hidden from view), the entire system is using Google's updated Roboto font, and you can now use Chrome for Android if you like.
AT&T was unable to give us a date for when the upgrade push will start, but if you've got a Vivid, we'd recommend you kick it off right now — don't bother waiting. And if you've got another legacy device on HTC's upgrade list, check the video to get a sense of what you can expect when your firmware finally comes.