Method and device for reducing signalling loads from a mobile device to a mobile telecommunications network system due to intersystem changes. The network system comprises a first and second radio access technology having a first and second radio access network and a first and second network core operable to page a mobile device via at least one element each of the first and second radio access technology. When idle or inactive state signalling reduction (“ISR”) is activated at the mobile device, the mobile device stores at least one first EPS bearer context and/or at least one first PDP context. After ISR is activated, at least one second EPS bearer context and/or at least one second PDP context is activated between the mobile device and the respective network. The respective network uses the stored at least one first contexts, or the at least one second contexts.