You should direct any queries regarding your license to licensehelpscirra.com, but basically, when your license is installed that's it.
You don't say whether you are licensed through Steam or via the traditional key-file.
I placed my original key-file in the install directory of C2 a long, long time ago and have never had an issue.
C2 is totally backward compatible. I can open (plugin dependent) any previous C2 program with the latest build.