updated 11:15 pm EDT, Fri March 23, 2012
ATT could skip keyboard and 4G patch
AT&T through its forums stated that it was passing on a a Windows Phone fix. Subscribers on the carrier wouldn't get the build 8107 fix, which fixes a common problem with the keyboard disappearing, for phones that didn't already ship with it preinstalled. A representative didn't have full information as to why, other than that AT&T was "not currently planning" to use it.
The update may be a prerequisite to LTE and is likely to be the minimum shipping build for two AT&T-first phones, the HTC Titan II and Nokia Lumia 900. As such, it's unlikely to be a compatibility issue.
Microsoft normally considers Windows Phone updates mandatory. It does have a clause, however, that lets carriers skip one minor update as long as they stay no more than one version behind. Why AT&T would feel a need to do this for a minor update isn't known, although it may feel that there's not enough urgency to the fix.
AT&T hasn't yet responded to complaints from users or to questions from the press. [via The Verge]