Sony is working on the wider availability of the Android 5.1.1 update that started with Xperia Z3 and Z2 devices in July. A similar firmware is now seeding for the older Xperia Z range with build version 10.7.A.0.222.
This means Xperia Z, ZR, ZL and Z Tablet could also receive all the goodies that the Z3 and Z2 models have been enjoying for a while now. These goodies are a blend of Google's latest Lollipop release and Sony software, and include improved customisation options, LinkedIn integration, camera enhancements and finally SmartWear integration, allowing users to take selfies with the SmartWatch 3 as a remote shutter button.
This release, according to the Xperiablog, does not patch the Stagefright vulnerability, although Sony has previously said it would release the security patches for the devices. Even the Xperia Z3 and Z2 range got the patches in the second firmware build 23.4.A.0.580 after the Android 5.1.1 was released with build 546. So, Sony might push out the fix with the next build. The update has already seeded for the C6602 and C6603 variants of Xperia Z, C6503 and C6506 models of ZR, Wi-Fi and LTE models of Tablet Z such as SGP311, SGP312, SGP321 respectively.
Sony is yet to update the software page for the above models. However, you can check the availability manually from Settings>> About Phone>> Software updates>> System updates. If the notification is yet to hit your region, you may use the FTF file shared by folks at the XDA forum, and install them manually using the Sony flash tool.
Xperia Z C6603 (Mena Arabic)
Xperia Z Tablet: Pre-rooted firmware for SGP312