The SR1 release changed a lot of SELinux handling aimed at Android 7.x. A bug in this handling caused the installation to break on older firmwares. This update fixes that specific bug.
This update focuses primarily on SELinux changes for Nougat:
Fixes an issue where the animation would keep running for quite some time after booting was complete, as seen on the S7 running the Nougat beta.
This update fixes some compatibility issues with a number of Nougat firmwares across various devices.
If you are not using a Pixel device, the only change in this SuperSU release is improved detection of file-based encryption. This should get rid of the issue where some Nexus devices suddenly got encrypted after flashing SuperSU.
This is a minor update, containing mostly bugfixes for cameras released this past year.
This update brings fixes primarily for devices with the A/B partition layout such as the Pixels, but there are some other fixes as well.
This update makes LiveBoot compatible with Android 7's new file-based-encryption mechanism.
Here's root for the new Pixels. This post doubles as release notes for SuperSU v2.78 SR2.