A user device (201; 1100) for communicating with a telecommunications network, comprising: a communications unit for receiving data; a notification unit for conveying a notification to a user; and a control unit for controlling operation of the communications unit and the notification unit ; wherein: the communications unit is configured to receive an information message ; and the communications unit is further configured to receive security authentication data associated with the information message if such security authentication data is available; characterised in that : the control unit is configured to operate either in a first configuration in which the control unit ignores the security authentication data if any and instructs the notification unit to convey the notification to the user , or a second configuration in which the control unit verifies the information message on the basis of the security authentication data and instructs the notification unit to convey the notification to the user if the verification is successful; the communications unit is configured to receive a configuration message comprising an indicated configuration that indicates whether the control unit should operate either in the first configuration or the second configuration ; and the control unit is configured to change configuration if the indicated configuration is different to a current configuration. a communications unit for receiving data; a notification unit for conveying a notification to a user; and a control unit for controlling operation of the communications unit and the notification unit ; wherein: the communications unit is configured to receive an information message ; and the communications unit is further configured to receive security authentication data associated with the information message if such security authentication data is available; the communications unit is configured to receive an information message ; and the communications unit is further configured to receive security authentication data associated with the information message if such security authentication data is available; characterised in that : the control unit is configured to operate either in a first configuration in which the control unit ignores the security authentication data if any and instructs the notification unit to convey the notification to the user , or a second configuration in which the control unit verifies the information message on the basis of the security authentication data and instructs the notification unit to convey the notification to the user if the verification is successful; the communications unit is configured to receive a configuration message comprising an indicated configuration that indicates whether the control unit should operate either in the first configuration or the second configuration ; and the control unit is configured to change configuration if the indicated configuration is different to a current configuration. the control unit is configured to operate either in a first configuration in which the control unit ignores the security authentication data if any and instructs the notification unit to convey the notification to the user , or a second configuration in which the control unit verifies the information message on the basis of the security authentication data and instructs the notification unit to convey the notification to the user if the verification is successful; the communications unit is configured to receive a configuration message comprising an indicated configuration that indicates whether the control unit should operate either in the first configuration or the second configuration ; and the control unit is configured to change configuration if the indicated configuration is different to a current configuration. <EOS>