While official support ended years ago, legacy communities (such as on 4PDA) have explored porting versions up to Android 6.0, though these often come with bugs and are mostly for experimental use. Official Support and Maintenance Official firmware updates are managed via the LG Mobile Support Tool Battery Efficiency:

Root the phone, then use or Chamelephon app to write back the original IMEI printed under the battery.

Follow these instructions meticulously. Skipping a step can result in a bricked device.