- Save the updater sequence as an array instead of object. - Warn only once. The compatibility is kept, but we should be able to break it as the config is not loaded in pickle model and it's declared to be not stable.
- Save the updater sequence as an array instead of object. - Warn only once. The compatibility is kept, but we should be able to break it as the config is not loaded in pickle model and it's declared to be not stable.