What version of gcc is required?

I have a linux server with no access to internet and no sudo privileges. So I cant install gcc with conda install libgcc.
I tried gcc --version on the server and it says 4.8.5. What version do I need to install to be able to run the process ?
Now I have following error when trying to execute python main.py....:
/lib64/libstdc++.so.6: version 'GLIBCXX_3.4.21' not found
