4. The method of claim 1 wherein the application server is a Private Branch eXchange ‘PBX’, the at least one additional feature being at least one additional Voice over Internet Protocol ‘VoIP’-based feature, the session communication protocol being based on SIP.
1. A method in a communications device comprising: the communications device accessing first features offered by an application of an application server from a plurality of application servers using a session communication protocol; the communications device obtaining a non-executable editable file that comprises (a) first information describing how to access at least one additional feature offered by the application of the application server for which the communications device was not previously configured to access and where the additional feature is specific to the application server and (b) second information describing how to represent the at least one additional feature; the communications device dynamically updating an existing Graphic User Interface ‘GUI’ so as to display a representation of the at least one additional feature offered by the application, in accordance with the second information; the communications device receiving input for selecting an additional feature of the at least one additional feature offered by the application via the GUI that has been dynamically updated; and the communications device accessing the additional feature offered by the application without having to change any compiled software on the communications device by using the session communication protocol in a manner for which the communications device was not previously configured to use or by using an extension of the session communication protocol in accordance with the first information.