Speaking for the Java API, from 10.0 to 10.1 the esriLicenseProductCode constants changed.
from esriLicenseProductCodeArcInfo to esriProductCodeAdvanced
So if you are checking for licensing in your code, you might run into this.
Can't say it will change again in 10.2. The Java docs for 10.2 point to the 10.1 publication. I have no idea about the .NET API.
But then again, 10.2 "is" a 10.1 service pack, right? Are they still calling it that?