impish Release no longer has a Release file

Question

I am trying to $ sudo apt update but I get this:

Reading package lists... Done                                                                                                                        
E: The repository 'http://archive.ubuntu.com/ubuntu impish 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 impish-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 impish-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 impish-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.

I haven't touched the Software & updates - other software OR the sources.list just in case some asks.

Exact Ubuntu version.

$ lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 21.10
Release:    21.10
Codename:   impish

Answer 1

For those who will find this post later on a more detailed answer is here 21.10 Removed Repositories

Support for Ubuntu 21.10 ended the 14th of July 2022 therefore you're going to have to upgrade.