As spotted by XperiaBlog, the new software has been signed off by wireless device certification forum the PTCRB. The update means the waterproof Z devices are one step behind the cutting edge of Google's software, 4.4 KitKat, with Sony's extra apps and features also upgraded.
Sony says the Jelly Bean update for the Z1 and Z Ultra has already started but "as usual, timing & availability may vary by market & carrier."
The update is set to bring the Xperia Z1's Smart Social Camera to other devices, which adds new camera apps from within the viewfinder as you're snapping away. Sony has also upgraded its own brand apps, such as Messaging, MyXperia, and the media player apps.
I'm interested in a mysterious new feature called Xperia Themes, described as a "unique custom interface experience." Sony hints at the ability to download a new look for your phone from online app and game store Sony Select -- it would be cool if you could really customise the interface, but let's face it, it'll probably just be some new colours for the home screen or something. Sony promises "more on this soon."
Sony wasn't kidding when it promised the update for the remaining Xperia phones was "right around the corner." The exact date has yet to be confirmed, and will largely depend on your network, but your phone will let you know when it's ready to update.
Are you looking forward to Jelly Bean, or do you feel left behind by the pace of Android updates? Tell me your thoughts in the comments or on our Facebook wall.