T-Mobile was very delayed in launching the Samsung Galaxy S4 on its network, but when it came to updating the latest smartphone, the carrier was really fast to deliver it to its subscribers.

T-Mobile has released a small but very important software update for Galaxy S4 devices running on its network, and the software update has reportedly landed with many small improvements.

"Beginning May 7, the Samsung Galaxy S 4 will have a software update to Android version 4.2.2/Baseband version M919UVUAMDL via OTA and Samsung Kies. This update improves the Visual Voicemail app and includes ISIS app improvements," T-Mobile posted on its support page.

The update is available over the air (OTA) with the version number M919UVUAMDL, but it can be flashed using Samsung KIES also.

The weight of the updated file is 168 MB and we suggest you to update it when you are connected to Wi-Fi so you can save you costly data usage.

You should also remember before going ahead with the updated that your devices should not have been rooted and should have at least 50 percent of battery backup before you start the entire installation process.

Meanwhile, AT&T users have also received a software update for their Galaxy S4 devices and the update is said to be a real booster of the smartphone's performance.

The update, with build number I337UCUAMDL, is very small when compared to the T-Mobile update. The update file weighs only 21.39 MB, but increases the smartphone's speed to a higher level.

Galaxy S4 users on the AT&T network are discussing their experience on Android Central's discussion forum, and most of them seem very pleased after updating their devices.

"Gallery is loading faster. Physical home button isn't lagging. Apps are loading quickly. Multi-tasking is even quicker with swiping away apps. Even the lock screen with the light effect isn't lagging. For those that remained patient for this past week and didn't overreact, pat yourselves on the back," a user posted.

The users are also finding that due to the update, the use of the RAM has decreased by almost 50 percent and that makes the functions of the device faster. According to them, the RAM use, which was around 1.2-1.3 GB earlier, has now come down to 650-700 MB.