Composer detected issues in your platform:require a PHP version ">= 8.0.0".

@vincej you could try the --ignore-platform-reqs:

https://getcomposer.org/doc/03-cli.md#install-i But there could be something else going on. Does all install and work.

Try the following and post what it returns (it will tell you want version composer finds)

composer -vvv about 

I thank you both for your responses. I am grateful. In the end, I gave up and just destroyed the server ( aka "droplet" in DigitalOcean speak) and reinstalled. So, problem solved the brute force way. Now I have everthing installed, I have a new problem to do with "rate limiter" not being found. But heah - it's Friday night, and tomorrow will bring a new day and a new post. Cheers! Vince.

I'm back. I hope you can help some more with composer which still giving me problems even after a reinstall.

Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 8.0.0".

And as before I am running php 8.0.12 and as before I get a clean result on all my dependancies.

I tried the --ignore-platform-reqs: and all I got then is an http:500.

This is a clean install of L8. There are no personal files or dir on the system, and I am not getting the welcome page. For the moment, my permissions are wide open to 777.

ok - so I did what @sinnbeck suggested, and got a curious statement saying it could not find the config for composer. Weird as it functions.

root@contraxiq:/var/www/html# composer -vvv about
Running 2.1.9 (2021-10-05 09:47:38) with PHP 8.0.12 on Linux / 5.4.0-89-generic
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Continue as root/super user [yes]?
Reading ./composer.json (/var/www/html/composer.json)
Loading config file ./composer.json (/var/www/html/composer.json)
Checked CA file /etc/ssl/certs/ca-certificates.crt: valid
Executing command (/var/www/html): git branch -a --no-color --no-abbrev -v
Executing command (/var/www/html): git describe --exact-match --tags
Executing command (CWD): git --version
Executing command (/var/www/html): git log --pretty="%H" -n1 HEAD --no-show-signature
Executing command (/var/www/html): hg branch
Executing command (/var/www/html): fossil branch list
Executing command (/var/www/html): fossil tag list
Executing command (/var/www/html): svn info --xml
Failed to initialize global composer: Composer could not find the config file: /root/.config/composer/composer.json

Reading /var/www/html/vendor/composer/installed.json
Composer - Dependency Manager for PHP - version 2.1.9
Composer is a dependency manager tracking local dependencies of your projects and libraries.
See https://getcomposer.org/ for more information.

Many thanks !!

I can't believe what I have just seen. When I do a php -v I get:

root@contraxiq:/var/www/html# php -v
PHP 8.0.12 (cli) (built: Oct 22 2021 12:34:48) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.12, Copyright (c) Zend Technologies
 with Zend OPcache v8.0.12, Copyright (c), by Zend Technologies

But when I run phpinfo() I'm getting PHP 7.4.3!!!! What the heck?