Trends for heating energy in European Cities are the decarbonization of energy sources and the reduction of heat loads. District heating (DH) networks are key systems to reach the targets due to the cost competitiveness and high performance levels they show. However, DH networks require a conversion to adapt for the need of the future. It is necessary to reduce the operation temperature so that it is possible to increase the performance of renewable systems and operation criteria needs to be adopted for the introduction of weather-dependent, distributed heat sources such as solar systems. In this paper is presented the RELaTED, a novel DH networks scheme with decentralized Ultra-Low Temperature performance. This way, it is possible the adaptation of new and existing networks to several operational schemes. Transitory phases for the conversion of actual DH and how this affects the whole system are discussed along the paper.