This Android 4.3 10.4.B.0.569 is only what is known as a file that has leaked which means that it is regarded as unofficial because it really has nothing to do with Sony at all, or the carrier for that matter because it is the carrier who decides when they want to roll something out.
The number 10.4.B.0.569 is the build number for this bit of software. That won’t match up with your previous copy which may have also been 4.3. If it’s the Zl your own, then after you install this there will also be some Android 4.2.2 features like on the menu made to match up with the flagship Z1 that had them already. We think that is just because it is custom, and the developers have thrown in something unique on their end. For the rest, it will have considerable upgrades for the 4.3 including stuff for the camera.
Even though this is unofficial, you will still lose any type of root access that you may have had before you installed it we think. Many places overseas away from the U.S are only just starting to get the first bit of this software. This even includes handsets like the Galaxy S3. Of course, there is also many people already using the KitKat which is another number up from this, and not just a new build code.
This is the newest Android 4.3 that there is available of any kind on the two Sony devices — Xperia Z and Xperia ZL.
To get a copy of yours just head over to this Dev-host link. Once you are inside you should see the file right away. There is only one on the page by itself.
We haven’t had the luxury of locating any instructions for getting the last build of Jelly Bean on the phones, but we assume it will be just like you normally would. It is coming out of the team as a real copy soon. For now, though, this is the only chance you have of getting it.
This all came about from an Asian website, hence the rather sketchy details about it. It’s hard to know exactly what they are saying and from there it becomes a bunch of Chinese whispers (no pun intended). Rumor has it that it will have a white UI.