It's more than a year, Samsung has not yet released any major update for it's yesteryear flagship devices, the Galaxy S3 and the Galaxy Note 2. But, Samsung is surely going to update both these devices to Android 4.3 Jelly Bean before the year end, along with this year flagship device Galaxy S4. If the folks of Sammobile are believed to be true, then Samsung has started testing Android 4.3 for the Galaxy Note 2.
According to Sammobile's report, Samsung will be updating the Galaxy S4 to Android 4.3 in October, followed by Galaxy S3 in November or October end, and finally the Galaxy Note 2 in December or November end.
There is also speculation that, Samsung will be also updating the Samsung Galaxy Mega 6.3 and Samsung Galaxy Mega 5.8 to Android 4.3 in upcoming months.
Currently the only Samsung devices running on Android 4.3 are, the Galaxy Note 3, the Galaxy Note 10.1 2014 Edition and the Galaxy Gear. In addition, Android 4.4 KitKat launch is around the horizon, and all the above mentioned Samsung devices will also get Android 4.4 KitKat.
Source - Sammobile