This document holds some tipps and tricks as well as solutions to common issues.
Make sure that the MCP client used supports cookies. The MCP-Session header is not enough for ICF based sessions!
This class is not fully downwards compatible, exclude the sub-package OAuth or delete the class. This class is only relevant for OAuth and if the interface does not exist your system is unlikely to support it.
Somehow abapgit sometimes does not recognize changes, probably due to the unusual coding structure after downport. Make sure to update all code and not just changed if this issue happens. If this does not solve it and you confirmed there is a real error in the code by checking GitHub sources (if possible) feel free to open an issue with details. Due to me not having a system < 7.50 it might be challenging to fix but I will have a look and do my best.
As per the specification there will be prefixes and therefore slashed in the keys of _meta data. You can use JSON Pointer notation to access those, e.g. "prefix/keyname" would be "prefix~1keyname", basicall replacing slash with ~1. This works for retrieving and setting those values.