Thanks to the folks at CyanogenMod, it looks like they have managed to bring Android 6.0 Marshmallow onto the device via the CM13 nightlies build. Given that it is a nightly build, it means that you probably should not use it as your daily driver because it isn’t quite ready for that just yet, but if you don’t mind taking it for a spin you can pop on over to the CyanogenMod website for the download.
However if you do encounter bugs, you should probably inform the developers so that it can be fixed. We’re not sure when the build for the Galaxy S3 will be stable and finalized, but it is a pretty good sign that at the very least it is being worked on. The Galaxy S3 isn’t the only older device to get the update.
Earlier this month we reported that the HTC HD2 managed to get an update to Android 6.0 thanks to the CM13 build. Considering the HD2 was released in 2009, it makes it seem “ancient” when compared to the Galaxy S3.