Android is a Linux-based mobile operating system developed for touchscreen mobile devices. It is developed by a consortium of companies known as the Open Handset Alliance (OHA), with the primary contributor and commercial marketer being Google. The Android operating system has evolved significantly since its inaugural release date. Android was officially launched to the public in 2008, with Android version 1.0. With the Android 1.5 Cupcake release in 2009, the tradition of naming Android versions after confectionery was born. The version names were also released in alphabetical order for the next 10 years. However, in 2019, Google announced that they were ending the confectionery-based naming, and were using numerical ordering for future versions. In the initial years, Android versions were updated more than twice a year, but in more recent years, version updates are done once per year. The most recent major Android update is Android 11, the eleventh major version of the Android operating system, announced by Google on February 19, 2020. 

The following is an overview of Android version history as of the time of writing:

This evolution has also dramatically impacted the security considerations of Android and how forensics techniques are applied. For example, the initial versions of Android did not have a Full Disk Encryption (FDE) mechanism to store data in an encrypted format within the device. As a result, extracting data from the device was much easier for a forensic investigator than it is currently. With each Android version update, more and more security features, such as app permissions, trusted execution environment (TEE), and secure kernel, have been added to improve the security of the platform overall but at the same time complicate the process of data extraction. We shall cover these security features in detail in the other sections of this chapter. 

Now that we know about the history and versions of Android, we will take a look at the Android architecture in the next section.