The embodiments herein relate to a method in a first mobility management node for handling updated subscriber data associated with a UE. The UE is currently unreachable by the first mobility management node. The first mobility management node receives, from a subscriber database, updated subscriber data associated with the UE. At least part of the updated subscriber data is modified. The first mobility management node determines that transmission of the updated subscriber data to a gateway node should be postponed until the UE has become reachable.