From Maties Ubuntu
Any version of Ubuntu that is not an LTS release should be considered testing versions not suitable for critical production use, but only to be used to prepare features for the next LTS release.
The latest LTS release is 16.04, the "Xenial Xerus"
LTS (Long Term Supported) versions of Ubuntu are available for critical production systems, which are released every two years and have five years free security support with expert paid technical support available from Canonical Ltd.
When a new LTS is released, you are welcome to upgrade, however Ubuntu advises that you wait until the first point release of the LTS upgrade is available, before you upgrade to a new LTS.
Click here to go to the upgrading wiki page.
- Newer Kernels and Software
Mark Shuttleworth and Canonical Ltd announced the creation of the Ubuntu Foundation and provided an initial funding of USD $10 million. The purpose of the foundation is to ensure the support and development for all future versions of Ubuntu.