CloudKit provides separate development and production environments for your record types and data. The development environment is a more flexible environment that is available only to members of your development team. When your app adds a new field to a record and saves that record in the development environment, the server updates the schema information automatically.
You can use this feature to make changes to your schema during development, which saves time. One caveat is that after you add a field to a record, the data type associated with that field cannot be changed programmatically. To change a field’s type, you must delete the field in CloudKit Dashboard and add it again with the new type.
Prior to deploying your app, you migrate your schema and data to the production environment using CloudKit Dashboard. When running against the production environment, the server prevents your app from changing the schema programmatically. You can still make changes with CloudKit Dashboard but attempts to add fields to a record in the production environment result in errors.
Note: iOS Simulator works only with the development environment. When you are ready to test your app in a production environment, do so from a device.
