Android Mascots At The Google I/O Developers Conference
Android mascots are lined up in the demonstration area at the Google I/O Developers Conference in the Moscone Center in San Francisco, California, May 10, 2011. Reuters/Beck Diefenbach

PTCRB--a North American certification forum comprised by cellular network operators which certifies new software for usage -

-certified on Nov. 7 a new firmware build version for older Sony Xperia Z Series. The models include Xperia Z, Xperia ZL, Xperia ZR and Xperia Tablet Z. The new firmware has the build version 10.5.1.A.0.292 expected to run the Android 4.4.4 KitKat due to similarities on the numerical codes used on the previous firmware build.

The previous build version, 10.5.1.A.0.283, was certified in Aug. 25. Here are the models supported by the new 10.5.1.A.0.292 firmware build version:

- Sony Xperia Z 2013: C6602, C6603 and C6606

- Sony Xperia ZL: C6502, C6503 and C6506

- Sony Xperia ZR: C5502 and C5503

- Sony Xperia Tablet Z: SGP321 and SGP341

Official software support webpages for older Sony Xperia Z devices confirmed the 10.5.1.A.0.283 as the latest available firmware. Below is the list of notable improvements added by Sony Mobile:

- Android 4.4.4 KitKat upgrade

- Better battery performance in some background applications

- Email stability and performance enhancements

- General improvements to MMS, Calendar, Wi-Fi, Contacts and more

- Latest bug fixes and enhancements

Android 5.0 Lollipop For Older Sony Xperia Z Series

Sony Xperia Z, Xperia ZL, Xperia ZR and Xperia Tablet Z are all eligible to the Android 5.0 Lollipop update coming in early 2015. Current status of software development of Android 5.0 includes the porting of the AOSP 5.0 Lollipop firmware to Xperia Z posted at XDA Developers Forum with working functionalities such as display screen, audio output, Wi-Fi, Bluetooth, GPS, sensors, Radio Interface Layer, NFC and more.

Official beta testing phase at Sony currently supports Xperia Z1, Xperia Z2 and Xperia Z3 AOSP 5.0 version. According to the company, owners of unlocked Xperia Z1, Z2 and Z3 smartphones can download the required files at the Developer World to test out the Android 5.0 firmware. As of now, there are no press releases yet of Android 5.0 testing on older Xperia Z devices, but users can check out the official listing here.