LG V20 is a lot different from the V10 and more like the better received LG G5. The LG V20 release date in September was the launch event but the phone won't come out until later this month.
The LG V20 has an Android 7.0 Nougat operating system, which is yet to be released so the LG V20 release date will follow the Google OS.
Android 7.0 Nougat should start rolling out this month and multiple sources suggest that the LG V20 release date is around October 21.
LG V20 will be the first phone that comes with the Android Nougat, therefore, this information also makes the release date sometime this month to be more likely.