Version resiliency for a host application and managed code

A method and architecture for increasing version resiliency between a host application that is unmanaged code and managed code is provided. A version resiliency technique specifies that the host application and the managed code communicate via an adapter that implements a protocol to access an object exposed by the host application. The version resiliency technique specifies that when a new version of the host application that impacts an interface exposed by the object of the host application is released, a new version of the adapter that executes within the application domain of the custom code is released. A version of managed code that adheres to the protocol will correctly interact with new versions of the host application that include a new version of the object because a new implementation of the adapter is also provided.