Sony Announces 4.3 Update Plans, Outlines Upgrade Process

Well now this was quick. Sony has made a frenzy of announcements this morning with the newly revealed Android 4.3. After teasing yesterday about the update, they have announced that 4.3 will be coming to the Xperia Z, ZL, ZR, Z Ultra, Tablet Z and SP. This makes sense, as they are all built on the same SoC as the Nexus 4 (excluding the Ultra which uses the more up to date 800), so Qualcomm should already have the drivers and whatnot working.

They have also stated that some devices on 4.1 will get directly updated to 4.3, but no word on which ones. Snuck in at the beginning was also the news that the Xperia ZR and Tablet Z will be getting 4.2 in early August.

On a developer blog post, they also outline their update process, which sheds some light on the level of work required to update and why it can take so long. If you want to know the nitty-gritty, you can check it out here, but the bottom line, is that the testing and certification phases take the longest, not the "Bring up" phase ("So it's not our fault?" lol). Also, they have spent some time working on their process, and, with the help of the PDK that Google has released, they have promised to shorten the update times. We have yet to see if the new processes will have a significant impact though.

And it would seem that Sony just doesn't want to quit. In a show of good faith, Sony has uploading some videos on youtube show the Xperia Z, ZL and Tablet Z already running the AOSP build of 4.3. It helps when they spend tons of time contributing to AOSP, their devices will already work and have few bugs.
Obviously the update is not ready for primetime, so I wouldn't try flashing it on your daily driver, but if you are adventurous, you can get the source here for the Xperia Z, Xperia ZL and Xperia Tablet Z on GitHub.

Source: Xperia Blog 1,2,3Sony Mobile; Sony Developer's Blog 1,2