How to do a rolling update

when switching an API shape

• find a way to determine between whether the request is an old request or a newer request
  • either through versioning or
  • through guessing the query parameters
• update the API endpoint
• keep the existing handler and use if when you detect that the request is sending an old format
• wait till there are no more requests to the old api
  • TODO: find a way to automatically notify devs of that
  • using warnDeprecated and kibana
• remove old handlers/functions, tighten validations