Thomas Göttgens c29bd00971 Rewrite the MQTT region root topic only on the default broker (#11899) ...

* fix(mqtt): rewrite the region root topic only on the default broker

A region change rewrote any root starting with "msh", on any broker. Custom roots such as msh/home were clobbered, and private brokers had their topics moved even though a regional broker is regional already. An empty root, which MQTT treats as the default, was never updated.

Region changes now go through MQTT::applyRegionRootTopic(), which rewrites the root only on the default broker and only when the root is empty, the default, or a msh/<region> the firmware wrote itself.

* fix(mqtt): parse the broker address before the default-server check

Persist module config only when the root actually changed. Replace a stray NUL byte in the test with the \0 escape.

* fix(mqtt): count the regional roots as the default root topic

2026-09-18 10:34:53 +00:00

..

MQTT.cpp

Rewrite the MQTT region root topic only on the default broker (#11899)

2026-09-18 10:34:53 +00:00