Another plan is to refactor code to be able to accept latest changes from upstream more easily. For the moment, many changes need to be done in original hpp and cpp files (like client.cpp, client.hpp, chain_database.cpp, chain_database.hpp,..etc.) and this makes update to latest upstream code difficult. API part is almost allowed to easily add extensions. My rough idea is to use classes inherited from these classes but I need time to figure out which is the best to way to do that.