Abstract: The invention relates to various embodiments of a method for updating a mobile agent (MA) providing services. The MA resides in a site in a data communications network. In a preferred embodiment a new MA, comprising the desired services, is created. The new MA moves to the site of the old MA where its data is customised. The method then waits until none of the old services in the old MA is running before it deactivates the old MA and activates the new MA. In addition, two further embodiments are provided. Furthermore, an interface manager (IM) for use with interpreted object-oriented programs is provided. The IM acts as a proxy for inter-object calls and has a redirection table in order to redirect object calls to objects that replaced old objects. Also, a method for updating an MA with an IM is provided.