Actually, that's never been confirmed. All we had was a screenshot (which could have been faked or wrong) and then nothing happening. So we don't know that there even is an update.
Actually, it was confirmed as pointed out by a Sprint representative on their forums.
They said that there was an update and it got delayed but it IS still coming. They also said that no matter what anyone tells you, it's not cancelled and no one knows what's really in the update.