However, the absence of the Xperia Z3 on that Nougat list is not Sony’s fault. Devices that get upgraded to new Android versions need to pass Google’s Compatibility Test Suite (CTS). The CTS was updated during the Android N Developer Preview programme which meant that to comply with the certification requirements, Sony never released the final preview (DP5) firmware on the Xperia Z3. The last update was the ‘DP4’ firmware.
So what exactly changed in the CTS? Well, it seems that Google now requires devices to have graphics that support either Vulkan or OpenGL ES 3.1. This means that any device that is now running Adreno 3XX graphics, such as the Xperia Z3’s Adreno 330 GPU as seen on all Snapdragon 800 and 801 chipsets, cannot be updated to Android 7.0. This is because the Snapdragon 800/801 only supports OpenGL ES 3.0.
So even if Sony wanted to deliver the official Android 7.0 update for the Xperia Z3 its hands were tied. Instead, you can blame Google for updating the CTS or you can blame Qualcomm for not supporting OpenGL ES 3.1, although to be fair to Qualcomm, OpenGL ES 3.1 was launched after the release of the Snapdragon 800/801 chipsets.
These thoughts were echoed by Sony developer Ola Olsson: “Even if we really wanted to give you N on the z3(c), we wouldn’t been able to do it. Not if we wanted to pass the Google CTS.” Another Sony developer, Zingo Andersen, went on to say: “The reasons are both technical and legal. If you followed the N Developer Preview program you know that we didn’t release the final DP5. That program ran into some unforeseen limitations that could not be resolved. This is the reason that both concept and official won’t be upgraded to Android N.”
So we can understand all of the frustration from Xperia Z3 users regarding no future Android 7.0 updates, but please don’t channel this frustration towards Sony. In this situation, there was little it could do.