How does one find what C++11 features have been implemented given a GLIBCXX version

Given a GLIBCXX version of the stdc++ library (example GLIBCXX_3.4.17) given this version, where would one find documentation which specifies what features have been implemented?

Further is there a way to which given the SO NAME version will provide the this same document.

I am working on an embedded system which has an existing version of libstdc++; unfortunately the supplied cross compiler (g++) is at a greater version than what the stdc++ library on the target supports. Upgrading the stdc++ library on the target is not an option. Before I write a lot of code, to only find that it does not run on the target; I would like to know beforehand what is and is not supported.

I have found the GNU Documentation to be useful; however, I am hoping there is a document in which one can get what has been implemented given the symbol version and/or the SO NAME and I just have somehow missed it.

Thanks for any help in advance