T-Mobile USA is in the process of issuing a carrier update for iPhones on its network that will add Visual Voicemail, LTE and HD Voice support for eligible devices.

As first noted by TmoNews, the operator posted a support document for the update, which is available to iPhones running iOS 6.1.x. Earlier today, T-Mobile began accepting pre-orders for the iPhone 5 in preparation for its official launch on the network next Friday.

The update, which was tipped earlier this week, comes over-the-air, but it has yet to appear on my phone. Other T-Mobile iPhone customers also report not having received the update.

Most of the exciting new features, such as AWS LTE, HD Voice and AWS HSPA+ are only for unlocked versions of the AT&T iPhone 5. Other iPhone users will, however, enjoy Visual Voicemail, a 4G network indicator, expanded MMS support and improved battery life.

T-Mobile announced its new “un-carrier” re-branding at an event last month, moving away from contracts and phone subsidies. It also hailed the official arrival of the iPhone on its network. When the device goes on sale next week, it will cost $99 up front with additional monthly $20 payments for the next two years. The carrier’s LTE network also went live in seven cities in March.

Here are the full details of the new version:

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)

Developing…

Image credit: Andrew Burton / Getty Images