Hello,
Unfortunately, ubus commands were always used internally and at your own risk, without a guarantee that shell commands or their output would remain unchanged. The latest 7.13.1 firmware release is an example where ubus command output has changed, and there is no way to revert this behavior.
Instead of ubus, we strongly recommend using API calls, which provide a more reliable and structured approach. You can find all necessary details for API Modbus calls here:
Best regards,