System and method for on-line replacement of software

A system for changing a software library during the execution of a software application using the software library. The software application interfaces to the software library only through the use of an interface library, to ensure that the software application does not directly bind with the software library. With no direct binding the software library can be updated during runtime without the software application re-resolving the location of the software library. The update is triggered by a change of the version number in a registry. The program correctness is maintained by library management services ensuring that the software library is no longer in use by the application before updating to the new library. Memory management services are used to ensure that the state of the library is maintained between the old and the updated versions of the software library.