Android does its rollouts in phases. Phase One is announced it at the Google I/O Conference in the summertime, getting everyone excited about the latest version of Android to their device. Phase Two is the rollout, and the first to receive it are Google's own Nexus devices for the year. Phase Three is when the new version rolls out to newer Android devices, and this can often take a while. When it comes to version 6.0 (also known as Android M or Marshmallow), it was predicted to come to LG quickly, at least for those in Europe. However, there were some problems, and here is what is known about the Android M version 6.0 Marshmallow update for LG G4, G3, G2 on carriers like Verizon, T-Mobile, Sprint, and AT&T.
About one month ago, LG was very excited to announce in a press release that LG customers in Poland to be the World's First to receive the Android upgrade on the company's current flagship phone, the G4. Unfortunately, there were some problems with it and Geek Snack said that the release of Marshmallow for the Poland rollout was "delayed indefinitely".
A new report from Android Origin states that LG was "quick to pick up on the issue, and now it is back to rolling out the Android 6.0 Marshmallow update on their flagship device". The Korean company wanted to upgrade the G4 as soon as the OS came out, but there was an undisclosed critical issue with Android 6.0 on LG G4 devices. It does look like Android M is rollout out in South Korea, but it might take two weeks to arrive.
As for when the Marshmallow update will be arriving at other countries, the International Business Times states that the LG G4 will receive its update in Europe from Q1 next year, possibly February 2016. Since the normal pattern of an Android rollout is go come to the newest devices first, and then the G Flex 2 is probably next to receive the update, followed by the G3 and the G2.
It should be known that some of these devices don't even have the latest version of the last major upgrade to Android: Lollipop (also known as version 5.0 or Android L). This version would be 5.1.1, made to fix bugs caused in the initial rollout of 5.0, and it is possible that devices like the G4, G3, and G2 will just skip Android 5.1.1 and go straight to 6.0.
There is still doubt whether Marshmallow will be even coming to the LG G3 and G2, as these are older devices, and it is often difficult to get the latest version of Android on any device that is over a year old. This shouldn't keep users of these devices from checking their Settings periodically, to see if there is a new update available.