1. A method of updating an implementation object including: creating a first implementation object including a first set of attributes or actions associated with an item of content included in a collection of managed content; creating a first proxy to provide users a first interface for accessing the first implementation object, including accessing the first set of attributes or actions; linking the first proxy to the first implementation object; using a processor to replace the first implementation object with a second implementation object including a second set of attributes or actions associated with the same item of content; creating a second proxy to provide users a second interface for accessing the second implementation object, including accessing the second set of attributes or actions; using the processor to link the first proxy to the second implementation object so that the first proxy provides a first user, who has possessed the first proxy prior to the replacement, the first interface for accessing a portion of the second set of attributes or actions that are accessible using the same first interface, wherein possessing the first proxy further comprises fetching the first proxy, and wherein providing the first user the first interface for accessing a portion of the second set of attributes or actions does not require re-fetching the second proxy; and linking the second proxy to the second implementation object so that the second proxy provides a second user, who fetches the second proxy after the replacement, the second interface for accessing the second set of attributes or actions.