According to InformationWeek, the US DoT has banned Microsoft's recent upgrades to Office, Windows and Internet Explorer.
In an internal memo dated January 19th, Daniel Mintz inserts that "there is no compelling technical or business case for upgrading to these new Microsoft software products. Furthermore, there appears (sic) to be specific reasons not to upgrade." As such, he has imposed an "indefinite moratorium" on upgrades from Office 2003 and Windows XP for its 15,000 desktop users.
In an interview on March 2nd, DoT CTO Tim Schmidt reconfirmed the ban, and explained that they were testing alternate platforms as possible replacements or compliments to a Windows offering. Included in those platforms are SuSe Linux and Apple's OS X.
While they have not entirely ruled out upgrades to Vista in the future, they are proceeding cautiously in order to avoid possible compatibility and stability issues that go along with such a significant upgrade.
The DoT is not the only Federal organization to impose such a ban. The Federal Aviation Administration, with nearly 45,000 desktops, has initiated a similar ban on upgrades for Microsoft products.