Improvements in Common Language Runtime (CLR) and Base Class Library (BCL).NET Framework 4 provides the following new features and improvements: Applications that are based on earlier versions of the Framework will continue to run on the version targeted by default. NET Framework 4 works side by side with older Framework versions. NET Framework is Microsoft's comprehensive and consistent programming model for building applications that have visually stunning user experiences, seamless and secure communication, and the ability to model a range of business processes.
