The 787 uses a variety of sound reducing mechanism including engines with characteristic chevrons:

[![enter image description here](https://i.stack.imgur.com/7cGEr.jpg)](https://i.stack.imgur.com/7cGEr.jpg)
(Source wikimedia commons)

Would it be possible for older airplanes to also have this type of quieter engine retrofitted? I'm assuming the engines would have to be recertified of course. **But do the chevrons implicate a particular type of wing or airframe that requires them to be designed in from the beginning?**