Kubuntu 19.04 Disco Dingo was released on April 18, 2019 with 9 months support. As of January 23, 2020, 19.04 reaches ‘end of life’. No more package updates will be accepted to 19.04, and it will be archived to old-releases.ubuntu.com in the coming weeks.
The official end of life announcement for Ubuntu as a whole can be found here .
Kubuntu 19.10 Eoan Ermine continues to be supported, receiving security and high-impact bugfix updates until July 2020.
Users of 19.04 can follow the Kubuntu 19.04 to 19.10 Upgrade  instructions.
Should for some reason your upgrade be delayed, and you find that the 18.10 repositories have been archived to old-releases.ubuntu.com, instructions to perform a EOL Upgrade can be found on the Ubuntu wiki .
Thank you for using Kubuntu 19.04 Disco Dingo.
The Kubuntu team.