As the newly released Kubuntu 19.04 makes its way into the world, inevitably other things come to their end.
Kubuntu 14.04 LTS was released in April 2014, and reaches ‘End of Life’ for support on 25th April 2019. All Kubuntu users should therefore switch to a newer supported release. Upgrades from 14.04 to a newer release are not advised, so please install a fresh copy of 18.04 or newer after running a backup of all your data.
Kubuntu 16.04 LTS was released on 21st April 2016, and was supported for Kubuntu for a period of year 3 years.* Kubuntu 16.04 LTS support therefore ends 21st April 2019, and users are invited to upgrade to 18.04 LTS, or perform a fresh install of that or newer release.
The Kubuntu team would thank users of both releases, especially for the amazing additional community support on IRC, forums, mailing lists, and elsewhere.