T-Mobile rolled out the Lollipop update for the LG G3 in April, which was later pulled for unknown reasons. The Uncarrier is now set to roll out the update once again, bringing the kernel version to Android 5.0.1.
According to T-Mobile's Des Smith:
T-Mobile Software Update: The new #LGG3 SW build is D85120e and should start rolling out to customers tonight after 12:01 am Pacific— Des (@askdes) June 9, 2015
According to users on our forums, it looks like the software version is Android 5.0.1. The update is now rolling out, so be sure to head into your device's setting to manually check if it is available.
Source: Twitter (Des)
Newer model: LG G4