Ubuntu 16.04 LTS is now available. From Canonical:
Canonical announced today it will release Ubuntu 16.04 LTS on 21st April, featuring the new ‘snap’ package format and LXD pure-container hypervisor. This is the latest version of the world’s most widely used Linux platform across desktop, IoT and cloud computing.
An Ubuntu Long Term Support (LTS) release is supported and maintained by Canonical for five years, making it the most stable, reliable, secure and cost-effective Linux platform for long-term, large-scale deployments. This is the 6th such LTS release for Ubuntu, and marks the first time that the platform is supported on mainframes, the world’s largest and most powerful Linux systems.