[troupo]

There are very few projects, in Javascript or elsewhere, that care about backwards compatibility the way React does.

You can still easily put a class-based component inside your modern hook-based codebase, and it will work (I did it this year :) )

But I think they kinda dripped the ball with Suspense and server components

[spion]

This is not the definition of backward compatibility I have in mind. Backward compatibility also includes "continuity", that is the new features flow from previous design.

React has been redesigned 2 times and now with server components its even less of an extension of previous ways of doing things.

Building 3 different frameworks where the old way to write code still works but nobody builds on top of that in any meaningfully useful way is a very minimal definition of "backward compatibility"