Creates a user if the user does not already exist, or updates an existing user identified by e-mail address or external ID. If you don't specify a role parameter, the new user is assigned the role of end user. If you need to create users without sending out a verification email, include a `"skip_verify_email": true` property in the body. #### External ID Case Sensitivity When providing an external id to identify an existing user to update, the search for the user record is not case sensitive. However, if an existing user is found, the system will update the user's external id to match the case of the external id used to find the user. #### Response Status Code - If the user exists in Zendesk, a successful request returns a 200 status code with "Location: /api/v2/users/{user_id}.json". - If the user does not exist in Zendesk, a successful request returns a 201 status code with "Location: /api/v2/users/{ne