Hi!
I have been running chirpstack for many years, since it was called loraserver, and the 3.x has been rock solid.
However, i finally took the time upgrading to v4 and it went reasonably well…
Data is coming from the sensors and most of them work great, som will not join again but that is a different issue…
But now i have a few problems i cant grasp… I have searched the forum front to back but either iam searching wrong or there isnt anythinging that match my problem.
Firts of all, downlink does not work…
I can add downlink messages to the queue both from chirpstack UI and from mqtt and i see them in UI but they do not reach the sensors.
I can se the messages in chirpstack log but there are no errors.
Like this one:
Feb 13 08:13:21 lorawan chirpstack[544934]: {“timestamp”:“2025-02-13T07:13:21.732222Z”,“level”:“INFO”,“fields”:{“message”:“Device queue-item updated”,“id”:“8b1cbb65-e168-4b40-9bea-c97b374a59cf”,“dev_eui”:“a81758fffe0c3f5f”},“target”:“chirpstack::storage::device_queue”,“span”:{“downlink_id”:3787484906,“name”:“data_down”},“spans”:[{“deduplication_id”:“25b75d8a-8e7b-4d30-915f-247040d34dca”,“name”:“up”},{“dev_eui”:“a81758fffe0c3f5f”,“name”:“data_up”},{“downlink_id”:3787484906,“name”:“data_down”}]}
Which matches this message
and i can se the message in mqtt at the gateway:
But it does not reach the sensor…
The gateways are Wifx Lorix One and while upgradeing i changed the mqtt templates of the gateway-bridge running in the gateways to reflect the added region “eu868” as below:
Event topic template.
event_topic_template=“eu868/gateway/{{ .GatewayID }}/event/{{ .EventType }}”
Command topic template.
command_topic_template=“eu868/gateway/{{ .GatewayID }}/command/#”
and changed marshaler to using protobuf instead of json as i understand that is a requrement in v4?
The logging in theese gw are close to none existent so iam having problems tho see what happens there but i figure as it was working before it is something that has changed in v4 or that i changed during the upgrade…
So i hope that someone can spot my mistake and guide me to a solution of my problem 
Running Chirpstack 4.11.0 on Ubuntu 24.04.02 LTS