There is provided a method, computer program, and apparatus for causing an apparatus for a first access node to perform: establishing a connection towards a user equipment via a serving cell supported by the first access node; instructing the user equipment to obtain a first timing advance value for a target cell supported by a second access node, wherein the first timing advance value indicates a timing for transmitting uplink transmissions to the target cell; receiving, from the user equipment, an indication that the first timing advance value is or will soon be invalid; and determining whether to instruct the user equipment to obtain a second timing advance value for the target cell in dependence on the received indication, the second timing advance value being obtained later in time than the first timing advance value.