Following the end-of-life of Ubuntu 12.04 LTS, Canonical is offering Ubuntu 12.04 ESM (Extended Security Maintenance), which provides important security fixes for the kernel and the most essential user space packages in Ubuntu 12.04. These updates are delivered in a secure, private archive exclusively available to Ubuntu Advantage customers on a per-node basis.
All Ubuntu 12.04 LTS users are encouraged to upgrade to Ubuntu 14.04 LTS or Ubuntu 16.04 LTS. But for those who cannot upgrade immediately, Ubuntu 12.04 ESM updates will help ensure the on-going security and integrity of Ubuntu 12.04 systems.
Users interested in Ubuntu 12.04 ESM updates can purchase Ubuntu Advantage at http://buy.ubuntu.com/ Credentials for the private archive will be available by the end-of-life date for Ubuntu 12.04 LTS (April 28, 2017).