One of the cool new things in Civil 3D and other AutoCAD based programs is the ability to, how we call it, "round-trip data" between different versions. If you remember, it was said numerous times before that Civil 3D is not backward compatible program, meaning that the drawings once saved in a new version were automatically upgraded and there was no easy way back. Now this is about to change. The reason I did not want to mention it earlier in our introduction to Civil 3D 2014 is that it comes with some caveats. Please be patient.
This (long) post will try to describe the behavior of certain features when an AutoCAD Civil 3D 2014 drawing is edited and saved in AutoCAD Civil 3D 2013 and then subsequently re-opened in AutoCAD Civil 3D 2014.