What are the best practices for managing PHP versions and dependencies when upgrading server operating systems?

When upgrading server operating systems, it is important to ensure that the PHP versions and dependencies are compatible with the new environment. To manage PHP versions and dependencies effectively, it is recommended to use a package manager like Composer to handle dependencies and keep track of required versions. Additionally, it is crucial to test the application thoroughly after upgrading to ensure that it works properly with the new PHP version.

// Example using Composer to manage PHP dependencies
// Add required PHP packages to composer.json file
{
    "require": {
        "php": "^7.4",
        "ext-mbstring": "*",
        "ext-curl": "*"
    }
}

// Install/update dependencies using Composer
composer install