Install PHP 8

Install the latest (currently PHP 8.0.*)

If you already have Apache + PHP installed, I would recommend to run a command to disable current version PHP (mine is 7.3) for Apache

sudo a2dismod php7.3

Add the repository

sudo wget -O /etc/apt/trusted.gpg.d/php.gpg
echo "deb $(lsb_release -sc) main" | sudo tee /etc/apt/sources.list.d/php.list
sudo apt update


Install Composer on Raspberry OS

I think it should work for both 32-bit and 64-bit Buster.

Step 1:

php -r "copy('', 'composer-setup.php');"
php -r "if (hash_file('sha384', 'composer-setup.php') === '795f976fe0ebd8b75f26a6dd68f78fd3453ce79f32ecb33e7fd087d39bfeb978342fb73ac986cd4f54edd0dc902601dc') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"