HTC has started rolling out the Android 5.1Lollipop update for the Developer Edition of the One M9.

According to the update's notification notes, the firmware upgrade comes with several major features that will improve the overall performance of the handset, Android Authority reported.

The main different between the standard One M9 and the Developer Edition is that the latter's bootloader is unlocked. This allows owners of the HTC One M9 Developer Edition to easily change the device's stock operating system with various versions of the Android OS.

In addition, the Developer Edition can be used on various carrier bands by simply switching SIM cards.

According to various sources, the update for the HTC One M9 Developer Edition is 794.32MB in size. Due to the large size of the file, users are advised to make sure that they are connected to a secure and stable Wi-Fi network before starting the download process. Users should also back-up their data and check if their devices have enough battery life before getting the update.

Based on the firmware update's notes, the Android 5.1 Lollipop comes with various enhancements such as Data Performance Improvements, Call Drop Improvements, Battery Life Improvements, Temperature Management Optimization and Camera Enhancements.

Out of all the features, the last two are probably the most significant.

For a while, HTC has struggled with complaints, rumors and other issues concerning the One M9's overheating problems due to its Snapdragon 810 processor.

Although it was previously clarified that this issue only affected the One M9's pre-released units, both HTC and Qualcomm continue to work on updates to eliminate the temperature-related problem.

As for the One M9's camera issues, several owners reported that the device sometimes produces washed out images, according to 9to5Google. Some also said that under unfavorable lighting conditions, yellow and blue hues appear in the photos.