If you are using SetNotificationPreferences, you can use the PayloadVersion field to specify the API version for all notifications for the calling application. If you are using GetNotificationPreferences, this field contains the API version for all notifications for the calling application. If you do not specify PayloadVersion in SetNotificationPreferences, the behavior of notifications is the same as it was before the PayloadVersion field was added to the schema. Before the PayloadVersion field was added to the schema, the API version for notifications was based on the API version specified as part of your SetNotificationPreferences call. Now, you can use PayloadVersion to override the API version specified as part of your SetNotificationPreferences call.
See the
Field Index to learn which calls use PayloadVersion.