In Trailblazer 2.1, we are introduced to a new concept: Activity.
Unlike Trailblazer 2.0, where Operation was king, activities have taken over as the main orchestrator of business logic. Good old operations are still there, but now they act as a wrapper around activities. Its one and the same, except activities are more powerful! Don’t worry though, its super easy to pick up and its backward compatibility makes switching a breaze.