What potential pitfalls should PHP developers be aware of when hosting their websites on different servers with varying PHP versions?

When hosting websites on servers with varying PHP versions, PHP developers should be aware of potential compatibility issues that may arise. To mitigate these pitfalls, developers can use version-specific checks in their code to ensure that it runs smoothly on different PHP versions. By checking the PHP version at runtime and adjusting the code accordingly, developers can ensure their websites function correctly across different server environments.

if (version_compare(PHP_VERSION, '7.0.0', '<')) {
    // Code specific to PHP versions below 7.0.0
} else {
    // Code for PHP 7.0.0 and above
}