There is no official statement from Sony yet regarding the Jelly Bean update, but the comments from the Sony UK product manager don’t bring any good news. So far, Cooper specifically confirmed that the Xperia arc S and Xperia mini pro won’t be getting the update.
The 2012 models, though, seemingly should get Android 4.1 Jelly Bean.
What’s disappointing here is that while ICS was a huge update requiring a lot of work from manufacturers, Jelly Bean is generally much lighter and with less core changes, and subsequently less work required to bring it to devices. Sony has earlier promised an 18-month support cycle for its products.
source: Sony UK via Xperia blog