How does the PHP version affect the ability to access constants?

The PHP version can affect the ability to access constants if the constant is defined using the `const` keyword inside a class. In PHP 5, constants defined in classes cannot be accessed using the `::` syntax outside of the class definition. This limitation was removed in PHP 7, allowing constants defined in classes to be accessed using the `::` syntax from outside the class. 

class MyClass {
    const MY_CONSTANT = 'Hello World';
}

// Accessing constant in PHP 7+
echo MyClass::MY_CONSTANT;

Keywords

PHP version constants access compatibility backward compatibility

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