The long-term support (LTS) releases of Ubuntu used to get support for five years. This is about to change apparently. Ubuntu 18.04, which we use on all our VPS modules, will now be supported for ten years. Other LTS releases might also get an extended support too.
The 10-years support announcement for Ubuntu 18.04 is driven by the needs of the IoT (Internet of Things) market.
Ubuntu 16.04, scheduled to reach its end of life in April 2021, will also be given a longer support life span.
What is not clear currently is whether the extended support is free of cost and if it is, will it be available to all the users including the desktop ones.