Substrate compatibility ?

[lucgerrits]

Hi,
I'm trying to build a C++ client using your Polkadot API CPP. A simple request like the system info works fine but when trying to view custom modules state storage it can't find the module. I later understood that a metadata version needs to match.
My Substrate node template is currently running with Metadata V12.

Is this Polkadot API CPP actually going to work with Substrate?
Is it possible to edit and add some custom metadata easily? If yes do you have any advice to jump-start my code?

Node version is: v2.0.1
My Metadata file looks like this:
metadatav12.txt

(The reason to use this lib with Substrate is to build a client that runs on a small IoT.)