Welcome back! If you missed Part 1, you can check it out here.
Schema Evolution and Compatibility
The key difference between schemas and APIs is that events with their schemas are stored for a long duration. Once you finish upgrading all the applications that call the API and move from API v1 to v2, you can safely assume that v1 is gone. Admittedly, this can take some time, but more often than not it is measured in weeks, not years. This is not the case with events where old versions of the schema could be stored forever.