Prominent tipster, LlabTooFeR, has tweeted that Qualcomm has not and will not release updated Vulkan API GPU drivers for the Snapdragon 800 and 801 chipsets that support Android 7.0 Nougat. Although a rumor at this point, this could be a major stopping point for any developer or company wishing to roll out Android 7.0 Nougat for a device based around one of these two chipsets: the Snapdragon 800 and 801 System-on-Chips were an incredibly successful and popular, used by many, many devices. We've already seen that Google has ended support for the much-loved Nexus 5, which is based around the Snapdragon 800 chipset. Sony have also confirmed that the Xperia Z3 family will not be receiving the update to Android 7.0 Nougat, plus devices such as the HTC One M8, which have dropped off HTC's supporting device list. This also means that the Samsung Galaxy S5, powered by the Qualcomm Snapdragon 801, will likely not receive an official update to Android 7.0 Nougat.
Qualcomm's Snapdragon 801 and 801 chipsets are based around a quad-core, 32-bit, "Krait" architecture, built on a 28nm process and including onboard networking and GPU technologies. Devices based around these chipsets run Android Marshmallow very well and so from a performance perspective, we can expect them to run Android 7.0 Nougat well. However, Qualcomm's decision highlights that there is more to a software update than simply if the application processor can run the code quickly enough: under the skin, the Snapdragon 800 and 801 chipsets are incompatible with the Vulkan API or perhaps are inefficient. It also gives Google an interesting take on the update situation: the Snapdragon 801 was a flagship chipset in early 2014 before being superseded by the Qualcomm Snapdragon 805 later in the year as used by the Motorola-built Nexus 6. However, there were still new devices being released with the Snapdragon 801 chipset in late 2014 so are inside the traditional two year time period when manufacturers support the device. It is likely that manufacturers will be unable to update these newer devices to Android 7.0 Nougat. Two of the latest devices to be released running the Qualcomm Snapdragon 801 are the OnePlus X and the ZTE Axon, which are now likely to officially remain on Android 6.0 Marshmallow.
However, this is Android! For customers willing to go down the unofficial route, all is not lost. We've already seen Android 7.0 Nougat ported to both the Nexus 5 and the 2013 Nexus 7, although without the official GPU drivers these devices might not be as stable as an officially supported device. It is possible that one or more manufacturers or developers will work on an updated GPU driver for the Snapdragon 800 and 801 chipsets. It is highly likely that developers are already working on Android 7.0 Nougat custom ROMs for the more popular Snapdragon 801-powered devices, including the HTC One M8, the 2014 Motorola Moto X, Samsung Galaxy S5 and the Sony Xperia Z3 family.