title: Is there an alternative for compiler directives in PHP in order to use app version?
body: <p>Here is the thing, I have a running application and my client has been asking me to add features over time. Now he hasn't implemented all the features that I've developed, but he wants to implement one feature recently developed. The thing is that there could be some incompatibility issues between the versions of the application that I made. </p>
  
  <p>I am wondering if I can add some sort of version directives to the methods of a class in php and somehow execute the ones that match with the web application version? </p>
  
  <p>I would appreciate greatly any kind of help that you could give me.</p>