Php-guide.7z

Classes should be open for extension but closed for modification.

The acronym represents five essential rules for high-quality software architecture: S: Single Responsibility Principle (SRP) php-guide.7z

If a Bird class has a fly() method, a Penguin subclass shouldn't override it to throw an error, as this violates the expectation that all birds in the system can fly. I: Interface Segregation Principle (ISP) Classes should be open for extension but closed