User blog comment:MisterWoodhouse/The first migrations to the Unified Community Platform/@comment-4432509-20200812121558/@comment-24006128-20200812131741

The old editor is deprecated and, yes, the new editor does have new features, like Find and Replace. It also has a mobile editor.

It is not optional, as we're updating the software running the platform. It's not simply a front-end design change like Reddit.