QFEs and the Default Version Policy
Quick Fix Engineering updates, or hot fixes, are unscheduled fixes that are sent out to address a major problem. Because a hot fix typically doesn't modify the code's interface, the chances that client code will be adversely affected are minimal. Therefore, the default versioning policy is to automatically associate all client code to the new "fixed" version of the code unless a configuration file exists for the application that explicitly associates the application with a specific version of an assembly. A new version of an assembly is considered to be a QFE if the only part of the version number that changed is the revision part.