Nowadays, the distribution network is subjected to several capacity challenges and congestion problems due to the growing number of distributed energy resources and new technologies such as solar photovoltaic (PV) energy, Electric Ve-hicles (EVs) and Battery Storage. Grid reinforcements are one of the traditional solutions to expand the network capacity, but are time consuming and sometimes not a cost-effective approach to address these sort of congestion problems. In the transition towards smart distribution networks, local flexibility on the de-mand-side can be employed as an alternative solution. In the Eu-ropean H2020 Interflex project, the enabling role of Distribution System Operators (DSOs) in calling for flexibility is investi-gated. The Dutch demonstration of this project has designed and implemented a flexibility (Flex) market model based on the Uni-versal System Energy Framework (USEF). The main goal is to enable local flexibility to address a day-ahead congestion prob-lem in parts of the Low Voltage (LV) grid. The proposed archi-tecture consists of the interactions between the local aggrega-tors, commercial aggregators and the DSO. The pilot has been implemented in the residential, urban area Strijp-S in Eindho-ven. In this paper, the final demonstration results of Interflex are presented. The field test results indicate that the imple-mented systems are capable of solving the day-ahead congestion problems. Nonetheless, there are uncertainties for the viability of a local flexibility market such as the complexity of the trading process, limited market liquidity and reliability of flex supply.