The Sony Xperia Z Ultra is one of my favorite devices of 2013, although I didn't buy one, unfortunately. The Z Ultra gets its name because it is based around a 6.4-inch, 1080p HD display and is powered by a Qualcomm Snapdragon 800 quad-core processor clocked at 2.2GHz with 2 GB of memory, 16 GB of storage and a MicroSD card. The Z Ultra has an 8 MP rear facing camera (no flash, though), a 2 MP front facing camera, high speed WiFi, 4G LTE (apart from the WiFi-only model) plus the usual associated radios. It's kept alive by a 3,050 mAh battery and it features water resistance, so this is a phablet that you can take almost anywhere with you. My reason for liking the Sony is because it could replace both my Nexus 7 tablet and my smartphone as the Z Ultra is voice-capable, but still fits into a front pocket. Unfortunately for Sony, the Z Ultra has not been the biggest commercial success, partially because it's something between a big phone and a small tablet (so it's too compromised in both respects).
Sony as a business and a manufacturer of Android devices have been releasing the source code for their devices associated with the AOSP (Android Open Source Project). In this case, the Z Ultra has not joined the club of devices with the software source code released, but it's very similar to the Xperia Z1 and this device does have the source released. Because of this fact, enterprising developer Saatvik Shukla has been able to successfully port Android 5.0 Lollipop across from the Z1 to the Z Ultra. However, the developer is keen to remind would-be users of the Lollipop ROM that this is for the regular Xperia version and not the Google Play Edition version. Whilst these devices have largely the same hardware, the internal configuration is different and attempting to flash Android Lollipop for the Xperia version onto the Google Play Edition will almost certainly brick your device. We understand that Google (and Sony) are to release the official over-the-air update for the Z Ultra in the near future but it's not yet out.
There are a number of issues with Android Lollipop on the Xperia Z Ultra as expected as the ROM is an early beta. Some of the issues reported by users include video playback, camera usage, LTE signal and GPS, but there are more issues out there probably. Because of this, it's arguably not ready as a daily driver (although I'm not sure why I write this, as these issues make the ROM even more suitable to manage with on a day by day basis, yes?). If you decide to install this ROM, be sure to let us know how you get on and if you find more bugs, let the developer know too!