2003 used MSSCCI 1.2. Visual Studio 2005, 2008, and 2010 use MSSCCI Version 1.3, which adds support for rename and delete propagation, as well as asynchronous opening.

Visual Studio supports running multiple instances of the environment (each with its own set of VSPackages). The instances use different registry hives (see official of the term "registry hive" in the sense used here) to store their configuration state and are differentiated by their AppId (Application ID). The instances