A number of recent comments by Sony UK suggest that the company will not provide Android 4.1 Jelly Bean upgrades to its 2011 Xperia device lineup. In a question and answer session conducted on Facebook, John Cooper, UK Product Manager for Sony Mobile, confirmed that neither the Sony Xperia Arc S nor the Sony Xperia Mini Pro would be upgraded to Android 4.1. In another comment, Cooper added that nothing to announce for the Sony Xperia S either.
While the comments do not mention a number of other 2011 models, the fact that the Xperia arc S was one of the more powerful ones suggests that lower-specced devices have little chance of seeing an upgrade either.
Technically, it would appear that any device running Android 4.0 should be able to run Android 4.1. It does require though that manufacturers devote resources to preparing, testing and supporting the upgrade package (assuming that there is nothing in their hardware or software preventing such a move). Not every company can and wants to do so, preferring instead that customers upgrade their device to a new one, a suggestion hinted at a few times in the Facebook exchange.
Sony has yet to give any hints about its Android 4.1 plans for its 2012 models.