Whilst the Samsung Galaxy S3 is over three years old now, Android 6.0 Marshmallow is apparently within its reach.
The news comes about as the Cyanogenmod 13 update (Android 6.0 Marshmallow) has been made available for the Samsung Galaxy S3 as well. And as surprising as it sounds, it works.
The Samsung Galaxy S3 with CM13 onboard runs pretty smoothly and keeps all major connectivity functions intact e.g. Bluetooth, mobile hotspot and the likes. This is impressive as its processor was originally designed for Android 4.0 Ice Cream Sandwich and eventually ran Jelly Bean before being left there.
So head on over to the CyanongenMod to download the required ROM to upgrade your Samsung Galaxy S3 to Android 6.0 Marshmallow. And remember, your device will need to be rooted.