If you are looking for new features to play with this will not be the Kernel for you. It is designed to improve the overall experience as if it was not there. At this point and probably never you wont find over clocking or voltage controls to play with but rather just a more efficient overall experience.
Each Kernel Download section contains a link to the commit list for both the purpose of following rules about posting links to Kernel Sources as well as serving as a change log. You will find in the main branch all Linux Kernel Increment Updates are grouped into one commit. This is to easily distinguish what commits have been made as part of the Linux Kernel Increment Updates from other additions/optimizations that are not part of the Linux Version Updates. You can find descriptions of each change made as part of the Increment Updates in the staging branch. In other words the second link below the download links will give a description off the changes made in the Linux Version Updates .
AOSP/Stock (Android Version 5.1.1)
AOSP/Stock Kernel is compiles using Google's GCC 4.8 toolchain and tested tested on the Stock 5.1.1 Rom as well as AOSP compiled Rom using unmodified pure 5.1.1 Source code. The Kernel may or may not work on custom Roms based on 5.1.1 depending on what changes have been made by the Roms developer and how far the Rom has strayed from the original source code. In most cases if the Rom is AOSP based the Kernel will work but provide no guarantee as am not testing with every ROM available. If you do find a Rom the Kernel does not work with feel free to comment but please include what Kernel was used that did not work as I may be able to shed light on reasons why and provide a workaround if possible. Most of incompatibility will find that the Kernel is not the issue rather what is included inside the boot.img like Ramdisk iinit.rc files that set permissions and create the Rom file-system.
Source / Change-log
Including individual explanation of changes included as part of Linux version increment update patches.
CM-12.1 Kernels may be updated more frequently without posting a new date so don’t be surprised to see multiple release number increments. In most cases there has been no change in the Kernel itself but update frequently as development is fast moving. Because of this some of the files that get packaged into the boot.img along with the Kernel may change and cause issues. Because of this will update as frequently as I can to insure everything packaged into the boot.img is up to date.
Source / Change-log
I am not responsible for any effect using the downloads from this forum my have on any device and you download and use at your own risk.