It is uncertain whether LG plans to release the Android 6.0 Marshmallow update for LG G3 or not.
It is unconfirmed that LG G3 and G2 will get the upcoming Android OS, according to Slash Gear. Google will be releasing the new upgrade in October, along with the launch of Google Nexus 5 2015.
There were rumors that LG may skip the Android 5.1.1 Lollipop update for LG G3 and LG G4 and will directly jump to Android Marshmallow. It is anticipated that LG G4 will get Android Marshmallow update sooner than the rest of the LG G series to be followed by the LG G3 in a couple of months.
LG is known to skip many updates and to roll out the major ones directly for their devices. In the past, it was seen that LG did not release the Android KitKat 4.4.4 update for its devices and directly rolled out the Android Lollipop 5.1 update.
Meanwhile, LG G Pad 2 10.1 and LG G Pad 10.1 are confirmed to get the Android Marshmallow update. It is also rumored that some of the LG devices will get the Vanilla version of Android Marshmallow. This Vanilla version of Android Marshmallow was originally designed for the Nexus devices.
Android Marshmallow is expected to come with major changes in the devices. It will provide support for the fingerprint reader, USB Type-C connection, and new Google Mobile Wallet, according to GSM Arena.
It will also provide support for Android Pay, which is very similar to Apple Pay. It will also introduce the feature of screen splitting in the devices, and also a better support for multi-tasking.