Hello @Balardo,

you are right - there was a bug in schema validation for /json/all endpoint. It should be fixed in the next release.

According to the direct Modbus unit register access - you can use e.g.
http://<your IP>/json/unit_register/UART_15_2_42

to get the ambient_light register:

{"status": "success", "data": {"name": "ambient_light", "value": 122.51519775390625, "glob_dev_id": 2, "dev": "unit_register", "circuit": "UART_15_2_42", "unit": "lux"}}

Register values has been also added to the web control panel:

01638744-d5ad-43e4-bc7f-e98cca7e5678-image.png

You can test it by install the test version:

sudo su apt update && apt install evok=2.3.3.test.20200923165635*