Sony Xperia Z has won many accolades from reviewers and it is one of the best smartphones released this year. However, the users of the Xperia Z handsets are very disappointed as the device is still running Android 4.1 Jelly Bean.

When Sony released the Xperia Z with Android 4.1 Jelly Bean, the company said that the smartphone will be updated to the Android 4.2 Jelly Bean firmware soon after the release, but that is yet to happen.

Sony is reportedly working on the new firmware and the highly-awaited Android update might land any time soon. According to a new report, two new firmware versions have been certified for Sony Xperia Z smartphone.

The new firmware versions were spotted on PCRB's website. According to the details given on the website, two firmware versions (10.1.1.A.1.319 and 10.3.A.0.407) were certified for Sony's products C6606 and C6616 on June 4.

The C6606 and C6616 are the codenames of the Xperia Z smartphone's two different versions that are going to head to the U.S. market.

The first firmware version looks very similar to the already certified firmware versions based on Android 4.1 Jelly Bean, but the second one comes with 10.3 version instead of 10.1 series. The change in the series forces everyone to think that the 'different' firmware version is going to be based on Android 4.2 Jelly Bean.

The Xperia Z (C6603) has recently received a new firmware update in Belgium, Hong Kong and Spain with build number 10.1.1.A.1.307.

Although the Sony Xperia Z has not reached the U.S. carriers so far, Sony CEO recently said that the device will not take very long to reach them.

At All Things D's D11 conference held last month, Sony CEO Kaz Hirai told reporters that the company is planning to sell the Xperia Z handsets through a major U.S. carrier shortly.

T-Mobile is rumored to be the frontrunner in the race to get the flagship device from Sony. At present, the Xperia Z is being sold in the U.S. only through the Sony Store. The smartphone is available for $629.99 without contract.