1. It's not "new" - it is the same program (mostly) that will be rewritten from Python to C++.
2. It's gradual work, and there is no time frame yet. You can use the current version - if it works for you, then you won't even notice any significant differences with the new version when it's released. When a new version becomes available, you'll just need to download the new executable file and panel modules.
3. All the same, should be even better in part of compatibility.