Although the latest Android 4.4.2 KitKat update is yet be rolled out to most of Samsung Electronics Co. Ltd.’s (KRX:005935) mid-range smartphones, the company is rumored to be already working on an Android 4.4.3 firmware update for some of its high-end flagship handsets.

The upcoming Android 4.4.3 KitKat update, with a build number KTU70, is currently being tested on both the Exynos and Snapdragon models of the Samsung Galaxy S5 and the LTE-A variant of the Galaxy S4 with the model number GT-I9506A, SamMobile reported Monday, citing insider sources.

According to the report, Samsung is testing the yet-to-be-released firmware by integrating it with its own software and features for now, which suggests that the update is not likely to be made available to the public for at least a month.

Meanwhile, Google Inc. (NASDAQ:GOOGL) is expected to roll out the Android 4.4.3 update by the end of this month or sometime in June, before its Google I/O conference, which is scheduled for June 25 and June 25 in San Francisco.

Samsung-Android-4.4.3 Samsung is rumored to be already working on Android 4.4.3 firmware update. Photo: SamMobile

In addition to the Samsung Galaxy S5, the Android 4.4.3 is also being tested on the Galaxy S4 LTE-A, which is yet to get Android 4.4.2, SamMobile reported, adding that the handset could skip directly to Android 4.4.3 in the future.

As for Samsung's mid-range smartphones, the company is expected to be on track to release the Android 4.4.2 firmware update for devices such as the Galaxy Grand 2, Galaxy Mega 5.8 and the Galaxy Mega 6.3. According to the report, all these devices are currently undergoing final testing and are likely to get the Android 4.4.2 update sometime in June.

Samsung-Android-4.4.2 Android 4.4.2 KitKat Update status. Photo: SamMobile

The SamMobile report also stated that some of these handsets -- like the Galaxy S4 LTE-A -- might skip directly to Android 4.4.3.