There is a current custom site definition which many sites are based on that needs to be re-worked. I am familiar (somewhat) with creating and deploying new site definitions through VS and creating sites based on that site definition, however I am wondering what limitations are there with regard to modifying the existing site definitions when sites have already been created using current.
For example MSDN says modifying site definition files to customize existing sites is not supported. Does mean I cannot update the existing site definition, or write a new one and apply that globally?. Appreciate the advice/help!