LG has just released the Android 8.1 Oreo kernel source code for the AT&T variant of the LG G5.
As you can see from above screenshot, LG has posted Oreo kernel sources for the LG H820, which is the AT&T version of the G5. This means the Oreo update should be rolling out soon to AT&T LG G5 H820.
On July 3rd, 2018, LG posted the Oreo kernel source code for the F700K, F700L, and F700S, which are Korean model names for the G5. and then on September 3, LG released the oreo Update for the LG G5 in South Korea. So We assume that AT&T LG G5 H820 will get the oreo update by the end of November 2018.
if you’re interested in the kernel sources, you can download the file from the link below!