The latest edition of Microsoft's mobile platform is no available as an upgrade for a pair of HTC-built smartphones offered by Sprint. You can now download and install Windows Mobile 6.1 for the HTC Mogul and Touch. The Mogul edition of the OS update is available here and Touch version here. Both are free. Windows Mobile 6.1 provides new timesaving features, easier phone navigation and management, stronger security safeguards, support for Microsoft System Center Mobile Device Manager 2008, and an improved Internet Explorer Mobile application, among other enhancements.