Failure capture has an error field plus data in the place we read as mode. Success capture also has both fields. Wrapper goes straight for data without checking the error.

Check the documented success condition before decoding data, and make an unfamiliar response fail visibly rather than selecting a default mode.

What will the trainee see when a read fails?

At present, last value. No indication it's old. I'll change that to unavailable with last successful reading time.

Keep the old value only if it's clearly historical. I'd rather see a blank than have to teach somebody that a normal-looking mode might be imaginary.

Fair enough. Main mode will be blank. Last good value can stay in the detail view, labelled with its time.

Yes, using saved responses now. Caught a malformed container that still slipped through. Adding that example to the checks too.

Do you still need to support the old SDK? I'd keep its interpretation separate if its response contract is different. Guessing the version from whatever fields arrive sounds fragile.

And include a successful response whose mode you do not recognise; success does not make every numeric value meaningful to your display.

Only new SDK required here. Wrapper now checks its documented result, structure and known modes. Saved success, failure, malformed and unknown-mode examples display correctly. Dashboard updated; failed reads show unavailable.

Thanks for posting the screen behaviour too. That's the bit I'd put in the trainee handout.