Unfortunately, this phone is just too new for there to be any Nougat ROMs for it. Everyone has Oreo on the Brain syndrome (yes, it's a real thing). The good news is that the stock ROM (Nougat 7.1.1) for this phone is pretty darn near AOSP, which I really like after having a Nexus 6 for the last two years. Nova Launcher goes a long way for pretty things up and adding some extra features, including round Pixel style icons. And then I edited my build.prop to get the stock wifi hotspot working, and I also tweaked some system stuff to enable and configure a rather hidden plain white LED notification/charge light. I've experienced the DU folks hatred (actually more like disregard) of Sprint firsthand when both the DU and PureNexus Marshmallow ROMs had several builds in a row where the kernel was causing my Nexus 6 to report that the SIM card was missing. I went from thinking it was a bad SIM to thinking it must be a bad SIM slot (or worse), to finally finding a couple other Sprint users who weren't encountering the problem at all. I was pretty much assuming it was a hardware issue with just my phone, when I realized that these other Sprint users were using a 3rd-party kernel rather than the stock DU/PN kernels. I flashed the 3rd-party kernel and POOF! SIM card came back. When I reported this easily reproducible issue to the DU/PN "staff", they didn't really seem to care and produced like 2 or 3 more builds with the exact same issue in their kernel. Eventually, they released a Nougat version of the ROMs and the problem went away. I'm still using LineageOS 14.1 on both of my sons' Samsung Galaxy S3 phones (one of them is still in use the other moved on to an iPhone 7, so I keep it going as a "hot backup"). I'm also using it on my Samsung Galaxy Note 10.1 2014 Edition tablet. I've received February security updates on both of those builds.