As a beginner, it can be quite challenging to grasp the meaning and purpose of the various branches in the AOSP (Android Open Source Project) source code. Branches like android-mainline, android-security, android-platform, android-qpr, and others can be confusing at first. Each of these branches serves a specific purpose and is used in different contexts within the development and maintenance of the Android operating system. This article aims to provide a comprehensive explanation of these branches, detailing their roles, how they are used, and why they are important. By the end of this article, you will have a clearer understanding of these branches and how they fit into the larger picture of Android development.

What is AOSP?

AOSP refers to the Android Open Source Project, which is a Linux-based operating system specifically designed for mobile platforms. This widely accepted project is the backbone of billions of devices around the world. It powers a vast array of gadgets, ranging from smartphones and tablets to cars, televisions, smartwatches, and even home appliances. The project is maintained by Google and allows developers to access the source code, enabling them to create custom versions of the Android operating system. This open-source nature has led to a diverse ecosystem of devices and applications, making Android one of the most versatile and widely used operating systems globally.

AOSP Release Cycle

Their is a Major android version release every year in the second quarter of the year. First its showcased in google's I/O in May and released between August to October. It is the successor of previous android version with All New Features and fixes.

QPR Releases

QPR refers to Quarterly Platform Releases. These updates are introduced every year following the major Android version release. They provide ongoing improvements, enhancements, and critical fixes to ensure the platform remains secure and up-to-date. Each year, there are a total of three QPR releases, typically spaced out evenly throughout the year. These updates address various issues reported by users and developers, and they may also introduce minor new features or optimizations to enhance the overall user experience. The goal of QPR releases is to maintain the stability and performance of the Android operating system between major version updates.

• QPR1 is released shortly after the main android release during January to February.

• QPR2 is released between April to May.

• QPR3 is released between July to August.

Android Point Release or .1 Release

Many android version like android 7,8 and 12 have seen a point release like 7.1, 8.1 and 12.1/12L. This makes a huge confusion that whats the point of these point releases. Why not to merge the features in the next QPR release or the next android version.

QPR releases generally target bug fixes, security patches and minor improvement. Whereas the Point Release Often targeted at fixing major bugs or performance problems identified after the main release. They might also include a few limited new features that weren't quite ready for the initial launch. For example

• 7.1 was a point release that introduced several new features, which might have been planned for Android 7.0 but were not ready at the time. These features included Split Screen, which allowed users to run two apps side by side, and the App Functional Shortcut menu, which provided quick access to specific app functions directly from the home screen. Additionally, it introduced a Beta Night Light mode, designed to reduce eye strain by adjusting the screen's color temperature in low light conditions. This release also addressed the annoying Private Platform API bug, which had been causing issues for developers and users alike.

• 8.1 brought a host of new features and improvements to the Android platform. One of the most notable additions was the introduction of safe browsing. Under the hood, there were significant improvements to Project Treble, which aimed to make it easier and faster for manufacturers to update devices to new versions of Android.

  In terms of user interface, there were several subtle yet impactful changes. The notification shade became translucent, providing a more modern and aesthetically pleasing look. Notification handling was also redefined, making it easier for users to manage and interact with their notifications. These changes, while seemingly minor, contributed to a smoother and more intuitive user experience.

  Additionally, Android 8.1 included various other enhancements and optimizations that improved overall performance and stability. These updates ensured that devices running Android 8.1 were more secure, efficient, and user-friendly, addressing both user needs and developer requirements.

• 12.1/12L primarily focused on adapting Android to large screen devices, such as tablets and foldable phones. This release was significant because it aimed to enhance the user experience on these larger devices, which have different needs compared to standard smartphones. The update included improvements to the user interface, making it more intuitive and user-friendly on bigger screens. Additionally, it introduced features like a taskbar for better multitasking, optimized app layouts, and enhanced drag-and-drop functionality. This release was closely aligned with the launch of devices like the Pixel Fold and various tablets, ensuring that Android could provide a seamless and efficient experience on these new form factors.

Security Patches

Every Android version receives support for three years, during which Google releases monthly security patches through the android-security branch. These patches are crucial for maintaining the security and integrity of the operating system. Each month, Google publishes an Android Security Bulletin that provides detailed information about the security issues that have been addressed in the latest patch. This bulletin includes descriptions of vulnerabilities, their potential impact, and the severity of the issues. By regularly updating their devices with these patches, users can protect themselves against known security threats and ensure their devices remain secure and functional.