Last November, Google released Android Jelly Bean 4.2.1 update to its now ubiquitous operating system and Samsung appears to be working hard to get the update on to its popular Galaxy S3 smartphone.

A new set of leaked screenshots of what claims to be the Android 4.2.1 test firmware for the Samsung Galaxy S3 has been unearthed by a member of the XDA-Developers forum. Releasing the screenshots, Sam Mobile, a reliable source for Samsung rumors, said the update will reach Galaxy S3 after the release of its much awaited successor Samsung Galaxy S4.

Some of the new enhancements in I9300XXUFMB3 firmware as listed out by Sam Mobile are:

 - Android 4.2.1 - JOP40D

 - Improved Ripple effect on lock screen

 - New Android 4.2.1 lock screen with widgets

 - Daydream (Settings>Display)

 - New Additions in Notification Center

 - Notifications are more actionable

 - Voice Command

It should be noted that Samsung released Android 4.1.2 Jelly Bean for the Samsung Galaxy S3 recently, bringing the Premium Suite including Galaxy Note 2′s Multi-Window View onto the best-selling smartphone. The South Korean electronic major has been quite steadfast in releasing timely software updates to its devices and we saw Android 4.1 update coming to Galaxy Note and Galaxy S2 as well.

Testing the firmware, Sam Mobile reports that it works just perfectly as any other official firmware. There firmware details are:

Android Version: 4.2.1 - JOP40D (Jelly Bean)

PDA: I9300XXUFMB3

CSC: I9300OJKFMB3

MODEM: N/A

Region: Middle East

Carrier: Unbranded

Changelist: 171637

Build Date: Feb. 19, 2013.

It should be noted that this is not the final firmware, but just a test firmware and so, there could be minor bugs. The report also includes complete flashing instructions (via Odin) in case you want to give it a try provided you have the international version of the Galaxy S3, model GT-I9300.

It's heavily rumored that Galaxy S4 will see an official launch on March 14, two weeks after the Mobile World Congress (MWC) event later this month in Barcelona. If that turns out to be true, Samsung Galaxy S3 will likely receive the Android 4.2.1 upgrade sometime in the later part of March or in early April.

You can download the firmware here: I9300XXUFMB3_I9300OJKFMB3_ILO.zip