How can developers ensure their code is compatible with both PHP 4 and PHP 5 when using classes?

Developers can ensure their code is compatible with both PHP 4 and PHP 5 when using classes by avoiding the use of PHP 5-specific features such as visibility keywords (public, private, protected) and magic methods (__construct, __destruct, __get, __set). Instead, they can use PHP 4-compatible syntax by declaring all class members as public and using constructor methods with the same name as the class.

class MyClass {
    var $property;

    function MyClass() {
        // Constructor code
    }

    function method() {
        // Method code
    }
}