Not able to install php 7.4 on Ubuntu 21.10 impish version

My ubuntu version:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 21.10
Release:    21.10
Codename:   impish

Now, I am trying to add ppa:ondrej/php repository using below commands:

$ sudo apt install software-properties-common
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
software-properties-common is already the newest version (0.99.13).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

sudo add-apt-repository ppa:ondrej/php
PPA publishes dbgsym, you may need to include 'main/debug' component
Repository: 'deb http://ppa.launchpad.net/ondrej/php/ubuntu/ impish main'
Description:
Co-installable PHP versions: PHP 5.6, PHP 7.x and most requested extensions are included. Only Supported Versions of PHP (http://php.net/supported-versions.php) for Supported Ubuntu Releases (https://wiki.ubuntu.com/Releases) are provided. Don't ask for end-of-life PHP versions or Ubuntu release, they won't be provided.

Debian oldstable and stable packages are provided as well: https://deb.sury.org/#debian-dpa

You can get more information about the packages at https://deb.sury.org

IMPORTANT: The <foo>-backports is now required on older Ubuntu releases.

BUGS&FEATURES: This PPA now has a issue tracker:
https://deb.sury.org/#bug-reporting

CAVEATS:
1. If you are using php-gearman, you need to add ppa:ondrej/pkg-gearman
2. If you are using apache2, you are advised to add ppa:ondrej/apache2
3. If you are using nginx, you are advised to add ppa:ondrej/nginx-mainline
   or ppa:ondrej/nginx

PLEASE READ: If you like my work and want to give me a little motivation, please consider donating regularly: https://donate.sury.org/

WARNING: add-apt-repository is broken with non-UTF-8 locales, see
https://github.com/oerdnj/deb.sury.org/issues/56 for workaround:

# LC_ALL=C.UTF-8 add-apt-repository ppa:ondrej/php
More info: https://launchpad.net/~ondrej/+archive/ubuntu/php
Adding repository.
Press [ENTER] to continue or Ctrl-c to cancel.
Adding deb entry to /etc/apt/sources.list.d/ondrej-ubuntu-php-impish.list
Adding disabled deb-src entry to /etc/apt/sources.list.d/ondrej-ubuntu-php-impish.list
Adding key to /etc/apt/trusted.gpg.d/ondrej-ubuntu-php.gpg with fingerprint 14AA40EC0831756756D7F66C4F4EA0AAE5267A6C
Hit:1 https://dl.google.com/linux/chrome/deb stable InRelease
Get:2 http://security.ubuntu.com/ubuntu impish-security InRelease [90.7 kB]                                     
Hit:3 http://ae.archive.ubuntu.com/ubuntu impish InRelease                                                      
Hit:4 http://ae.archive.ubuntu.com/ubuntu hirsute InRelease                                 
Get:5 http://ae.archive.ubuntu.com/ubuntu impish-updates InRelease [90.7 kB]                
Hit:6 http://ae.archive.ubuntu.com/ubuntu impish-backports InRelease                                    
Ign:7 http://ppa.launchpad.net/ondrej/php/ubuntu impish InRelease
Err:8 http://ppa.launchpad.net/ondrej/php/ubuntu impish Release
  404  Not Found [IP: 91.189.95.85 80]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/ondrej/php/ubuntu impish 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.

As you can see it gives error message E: The repository 'http://ppa.launchpad.net/ondrej/php/ubuntu impish Release' does not have a Release file.

And I am not able to install php 7.4 after this using sudo apt-get install php7.4

My question is how to install php 7.4 on this version of Ubuntu?


You have to wait until packages for this new Ubuntu version are released in OndrejSury repository.

https://launchpad.net/~ondrej/+archive/ubuntu/php?field.series_filter=

If you look now he currently supports versions 18.04 (bionic), 20.04 (focal) and 21.04 (hirsute).

When he will add packages for 21.10 (impish), then you will be able to add this repository.