Android N Developer Preview 3 can now be rooted! Chainfire has just released his update to SuperSu. This brings SuperSu to version 2.74 Beta. The new build includes support for the N Preview 3, but also the new build of SuperSu includes a fix for Samsung Security Policy updates. A few days ago Samsung users lost root suddenly when they received a security policy update.
Not only does this version of SuperSu fix the Samsung Security Policy update issue it also prevents further updates from coming through and killing root unexpectedly. Apparently if you have lost root on a Samsung device due to the Security Policy update you will need to first restore your boot.img backup, or flash back to stock if you don't have a boot.img backup, then flash the new SuperSu. Head to the link below for more info and download links.
via +Chainfire