Hi PBM, I’m sorry that this cought you unaware.
Yes this is an intentional change to make it easier for us humans to read and has been syncronized with support in the ThermIQ-web poller and HomeAssistant integration as well as the documentation. The old notation is still allowed when sending writes.
It’s possible to revert back to old, hex-format, rXX by:
ThermIQ/ThermIQ-mqtt/set {”REGFMT”:0}
See also the documentation at:
http://thermiq.net/ThermIQ_MQTT_Installation.pdf