Repository does have released file error while updateting apt

Question

I am constantly getting the code above, some repositories does not have released file. Full log of sudo apt update:

Hit:1 http://security.ubuntu.com/ubuntu trusty-security InRelease
Hit:2 http://ppa.launchpad.net/git-core/ppa/ubuntu disco InRelease                                     
Hit:3 http://packages.microsoft.com/repos/vscode stable InRelease                                      
Hit:4 https://artifacts.elastic.co/packages/7.x/apt stable InRelease                                   
Ign:5 http://security.ubuntu.com/ubuntu disco-security InRelease                                     
Err:6 http://security.ubuntu.com/ubuntu disco-security Release
  404  Not Found [IP: 2001:67c:1360:8001::24 80]
Ign:7 http://archive.ubuntu.com/ubuntu disco InRelease
Ign:8 http://archive.ubuntu.com/ubuntu disco-updates InRelease
Ign:9 http://archive.ubuntu.com/ubuntu disco-backports InRelease
Ign:10 http://archive.ubuntu.com/ubuntu lucid-backports InRelease
Err:11 http://archive.ubuntu.com/ubuntu disco Release
  404  Not Found [IP: 2001:67c:1562::18 80]
Err:12 http://archive.ubuntu.com/ubuntu disco-updates Release
  404  Not Found [IP: 2001:67c:1562::18 80]
Err:13 http://archive.ubuntu.com/ubuntu disco-backports Release
  404  Not Found [IP: 2001:67c:1562::18 80]
Err:14 http://archive.ubuntu.com/ubuntu lucid-backports Release
  404  Not Found [IP: 2001:67c:1562::18 80]
Reading package lists... Done
E: The repository 'http://security.ubuntu.com/ubuntu disco-security Release' no longer has 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://archive.ubuntu.com/ubuntu disco Release' no longer has 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://archive.ubuntu.com/ubuntu disco-updates Release' no longer has 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://archive.ubuntu.com/ubuntu disco-backports Release' no longer has 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://archive.ubuntu.com/ubuntu lucid-backports 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.

My /etc/apt/sources.list:

deb http://archive.ubuntu.com/ubuntu disco main universe restricted multiverse
deb http://security.ubuntu.com/ubuntu trusty-security main universe

deb http://security.ubuntu.com/ubuntu/ disco-security universe main restricted multiverse
deb http://archive.ubuntu.com/ubuntu disco-updates universe main restricted multiverse
deb http://archive.ubuntu.com/ubuntu disco-backports universe main restricted multiverse
deb http://archive.ubuntu.com/ubuntu lucid-backports main restricted universe multiverse

Should I delete some sources from the file above? Which?

EDIT: cat /etc/os-release:

NAME="Ubuntu"
VERSION="19.04 (Disco Dingo)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 19.04"
VERSION_ID="19.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=disco
UBUNTU_CODENAME=disco

grep -r ^deb /etc/apt/ --include "*.list":

/etc/apt/sources.list:deb http://security.ubuntu.com/ubuntu trusty-security main universe
/etc/apt/sources.list.d/vscode.list:deb [arch=amd64] http://packages.microsoft.com/repos/vscode stable main
/etc/apt/sources.list.d/elastic-7.x.list:deb https://artifacts.elastic.co/packages/7.x/apt stable main
/etc/apt/sources.list.d/git-core-ubuntu-ppa-disco.list:deb http://ppa.launchpad.net/git-core/ppa/ubuntu disco main
/etc/apt/sources.list.d/git-core-ubuntu-ppa-disco.list:deb-src http://ppa.launchpad.net/git-core/ppa/ubuntu disco main

Answer 1

As it was already mentioned both 14.04 LTS (trusty) and 19.04 (disco) are EOL.

So if you want to save currently running system you need to fix sources.list first to the disco version and then upgrade it to currently supported release - 19.10 (eoan).

At first we need to fix the /etc/apt/sources.list to normal repository lines. You have to open it with any text editor like pkexec gedit /etc/apt/sources.list and fill it with following contents:

deb http://old-releases.ubuntu.com/ubuntu/ disco main restricted
deb http://old-releases.ubuntu.com/ubuntu/ disco-updates main restricted
deb http://old-releases.ubuntu.com/ubuntu/ disco universe
deb http://old-releases.ubuntu.com/ubuntu/ disco-updates universe
deb http://old-releases.ubuntu.com/ubuntu/ disco multiverse
deb http://old-releases.ubuntu.com/ubuntu/ disco-updates multiverse
deb http://old-releases.ubuntu.com/ubuntu/ disco-backports main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu disco-security main restricted
deb http://old-releases.ubuntu.com/ubuntu disco-security universe
deb http://old-releases.ubuntu.com/ubuntu disco-security multiverse

Also do not forget to comment lines with lucid and trusty and save the file. Then update package lists and install all upgrades with:

sudo apt update
sudo apt dist-upgrade

Then upgrade this system to 19.10 by running do-release-upgrade.