I have attached a screenshot of the message I get when using sudo apt-get update.
I attempted to use the repositories in the past but did not succeed. I now wish to get rid of these messages.
Any advice on where to go and remove these entries? Probably a config file I have to edit.
E: The repository 'http://ppa.launchpad.net/falk-t-j/qtsixa/ubuntu disco Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/materieller/teamspeak3/ubuntu disco Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
I am using Kubuntu version 19.04, KDE PLasma version 5.15.4
Thanks