http://www.htc.com/us/faq_detail.aspx?p_id=75&act=sd
edit by No2Chem:
Why update the ROM on your device?
The software upgrade posted below provides several key enhancements for your Mogul:
1. Upgrades the operating system from Windows Mobile® 6.0 Professional to Windows Mobile® 6.1 Professional
2. Adds Sprint TV
3. Includes all enhancements incorporated in previous software upgrades including: EV-DO Rev. A functionality for faster download and upload speeds when utilizing data services wherever EV-DO Rev. A coverage is available.
Advanced GPS functionality including the Sprint Navigation application.
Adds a Task Manager to the Today screen for easier access and management of running programs.
Please bookmark this page for easy reference for any future software upgrades.
Posted July 21, 2008
Download Mogul by HTC WM6.1 and SprintTV Update – Version 3.56.651.0
HTC's servers are CACHED, so you might not see the updated rom until after a few refreshes. This is ROM 3.56.651, which is the same ROM that was leaked a few weeks ago. It boasts, among other things WM 6.1
Known Issue: Sprint Voicemail Alert Today Plugin removed. Reinstall it with cab provided
here.