Upgrade 117.x wrecked REST command

The following command, amongst other rest commands, fails to operate after upgrade to 117.0 or 117.2

- platform: rest
  resource: http://xxx.xxx.xxx.xxx:10000/retrieve
  method: POST
  payload: '{"retrieve_message": {"seqnr": 1,"account_auth": {"user_account": "","mac_address": "xx:xx:xx:xx:xx:xx"},"info": 8}}'
  name: room_temp
  value_template: '{{ value_json.retrieve_reply.report.room_temp }}'
  unit_of_measurement: "°C"

Restored back to 116.4 and all is functioning again! Any suggestions what may have changed following the upgrade which warrants update of the rest command?