We have just released zcashd 2.1.1-1 to our Debian apt repository. It includes a soft-fork change to the consensus rules to address a security vulnerability that could be leveraged to cause consensus forks. We request miners and pools upgrade as soon as possible to ensure this soft-fork is activated. We also request all users to upgrade as soon as possible.
Please see the following for more information: https://electriccoin.co/blog/new-releases-2-1-1-and-hotfix-2-1-1-1/