Request: Optional legacy flat MQTT topics for ioBroker / OpenHAB / non-HomeAssistant users

[tobintax]

Hi, first of all thank you for this great project – it works perfectly.
I'm using the device outside of Home Assistant (ioBroker), and I noticed that the firmware only publishes a single JSON state under:

otthing//state

This works well for HA and systems with native integration, but systems like ioBroker, OpenHAB or Node-RED often rely on flat MQTT topics, e.g.

otthing//flow_t
otthing//return_t
otthing//dhw_t
otthing//outsideTemp
otthing//ch_pressure
otthing//rel_mod
otthing//status/flame
...

Right now every non-HA environment needs to parse the JSON manually and create its own hierarchy, which is possible but not very convenient.

Proposed solution

Add an optional configuration flag, e.g.:
legacyMqttTopics: true/false

When enabled, the firmware would additionally publish a set of flat MQTT topics for the most relevant values. When disabled, the behavior would stay 100% identical to the current version (HA discovery + JSON /state only).

Why this helps

• Makes integration with ioBroker, OpenHAB, Node-RED much easier
• Does not change the default behavior for Home Assistant
• No breaking changes
• Only publishes extra topics when explicitly enabled

Willing to contribute

If you agree that this could be useful, I would be happy to prepare a Pull Request that adds this feature in an optional, non-intrusive way.

Would you be open to this?

Thanks!

[Phunkafizer]

Good idea. I'd suggest to send these immediately and once per reception from bus.
A flag could be added to the OTValue class and, if set, be messaged in the loop.