How can developers ensure compatibility and smooth transition between different PHP versions in their development and production environments?

To ensure compatibility and smooth transition between different PHP versions in development and production environments, developers can use version control systems like Git to manage their codebase and dependencies. They should also regularly test their code on different PHP versions and keep an eye on deprecated features or changes in newer versions.

// Example code snippet demonstrating the use of version control and testing for PHP compatibility
// This is a simple PHP script that checks if the current PHP version is compatible with the code

if (version_compare(PHP_VERSION, '7.0.0', '<')) {
    echo 'This code requires PHP 7.0 or higher';
    // Handle compatibility issues or provide instructions for updating PHP version
} else {
    // Code that should run on PHP 7.0 or higher
}