There were a few rumors and maybe confusion about LG WebOS platform Updates that are firmware new versions instead. We made some questions to LG Electronics LGUS about it and they answered as follows:
So, The LG webOS 3.5 is the latest and current webOS platform that is employed on the 2017 LG TVs. This platform was covered in announcements made during CES2017 which can be found at LGNewsroom
Finally, there are no new LG WebOS platform updates at this time from version 3.5 as was rumored.