The AOSP common kernels (also known as the Android common kernels or ACKs) are downstream of kernel.org kernels and include patches of interest to the Android community that haven’t been merged into mainline or Long Term Supported (LTS) kernels.

What is the Android kernel?

A kernel in an operating system—in this case Android—is the component responsible for helping your applications communicate with your hardware. … It’s the operating system you use on your phone, the software your phone uses to get things done—the kernel is the bridge between that ROM and your hardware.

What is the latest Android kernel version?

The current stable version is Android 11, released on September 8, 2020.
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Android (operating system)