A method executed at a first mobile device, the method comprising: sending, to a network node, first device-to-device capability information for the first mobile device, the first device-to-device capability information being associated with device-to-device direct connection functionality supported by the first mobile device, wherein the first device-to-device capability information indicates whether the first mobile device is able to discover one or more other devices in proximity to the first mobile device; receiving, from the network node, second device-to-device capability information for a second mobile device associated with a contact stored in the first mobile device, the second device-to-device capability information being associated with device-to-device direct connection functionality supported by the second device, wherein the second device-to-device capability information indicates whether the second mobile device is discoverable by one or more other devices in proximity to second mobile device; determining, based on the first device-to-device capability information and the second device-to-device capability information, whether the second device is discoverable by the first mobile device; in response to determining that the second mobile device is discoverable by the first mobile device, determining whether the second mobile device is in proximity to the first mobile device; and in response to determining that the second mobile device is in proximity to the first mobile device, setting an indicator in an address book of the first mobile device to indicate that a proximity service associated with the second mobile device is available. sending, to a network node, first device-to-device capability information for the first mobile device, the first device-to-device capability information being associated with device-to-device direct connection functionality supported by the first mobile device, wherein the first device-to-device capability information indicates whether the first mobile device is able to discover one or more other devices in proximity to the first mobile device; receiving, from the network node, second device-to-device capability information for a second mobile device associated with a contact stored in the first mobile device, the second device-to-device capability information being associated with device-to-device direct connection functionality supported by the second device, wherein the second device-to-device capability information indicates whether the second mobile device is discoverable by one or more other devices in proximity to second mobile device; determining, based on the first device-to-device capability information and the second device-to-device capability information, whether the second device is discoverable by the first mobile device; in response to determining that the second mobile device is discoverable by the first mobile device, determining whether the second mobile device is in proximity to the first mobile device; and in response to determining that the second mobile device is in proximity to the first mobile device, setting an indicator in an address book of the first mobile device to indicate that a proximity service associated with the second mobile device is available.