You may want to use this pasigono repo for inspiration instead. I’m not the developer so am not sure exactly what changed, but the raw_printing app was developed on something like version 13.5/13.6. It worked with that, but since that time, there were some breaking changes in more recent versions. The pasigono repo was updated (and some other POS features were added) and is verified working with 13.17 and 13.18.