Currently the method to update a user (PUT /user?username=USERNAME) will replace the existing user entry with the payload. This means that even if you're just updating one attribute, all attributes will need to be explicitly defined in the payload when using this call. Any attributes not in the payload will be set to a NULL value.

This means that typically a GET /user?username=USERNAME&expand=attributes request will be needed to retrieve the user's current attributes, and then parsed to construct the PUT payload. This can be inconvenient.

This product improvement request is to implement a new REST call so that individual user attributes can be updated without affecting the others.