T-Mobile announces iPhone carrier update with support for Visual Voicemail, 4G LTE and HD Voice [UPDATED]

Remember that T-Mobile Carrier Update for iPhones that we told you about earlier this week? Yeah, it's now official. T-Mobile just posted the details of the update in its support forums, revealing both the information on how to obtain the update as well as an official changelog. The update is available for all eligible iPhones with a T-Mobile SIM card, and it can be downloaded either over the air (using a cellular or Wi-Fi connection) or through iTunes. Here's the full rundown of the update as provided by T-Mobile:

T-Mobile Carrier Update

Version

• iOS software version 6.1
• Updated 4/05/2013
• Available to all eligible iPhones using a T-Mobile SIM card

Features

• Enables the following:
  • Visual Voicemail
  • 4G network indicator
  • Commercial Mobile Alert System (CMAS)
  • AWS LTE (T-Mobile and officially unlocked AT&T iPhone 5 only)
  • HD Voice (T-Mobile and officially unlocked AT&T iPhone 5 only)
  • AWS HSPA+ (T-Mobile and new 2013 AT&T iPhone 5 only)
• Auto configures:
  • MMS Settings
  • Personal Hotspot Settings (Smartphone Mobile Hotspot)
  • APN settings for LTE connectivity
  • My Account bookmark

Improvements

• Battery life (result of network/device optimization)

Prerequisites

• T-Mobile iPhone or any officially unlocked GSM iPhone
• Latest iOS software version
• Device software is not jailbroken
• 50% battery life or connected to a power source
• Data connection or a computer with iTunes and internet access
• Minimum of 1 MB available memory (File size of update is ~10 KB)

That's a pretty significant update, especially for iPhone 5 models that'll be gaining LTE and HD Voice support. Even non-iPhone 5 models will benefit from the update, though, especially thanks to the battery life improvements that will come from the network and device optimization that's included.

T-Mobile lists the update as being available today, but it's possible that the update isn't available quite yet since this changelog was just posted. If you've got a T-Mobile iPhone and want to check for the update yourself, you can head on in to Settings > General > About. A pop-up should appear if there's an update available. Be sure to give us a shout in the comments below once the T-Mobile Carrier Update hits your iPhone!

UPDATE: The official T-Mobile Twitter support account, @TMobileHelp, has told several users that the Carrier Update has been postponed. There's no word yet on what's caused the delay or when the update might begin rolling out, but we'll share more details with you as we get 'em.

Via TmoNews, T-Mobile, @TMobileHelp