Verification and testing of concurrent programs is challenged by the combinatorial explosion that arises by considering all possible ways in which processes/threads can interleave. Partial Order Reduction (POR) techniques eliminate redundancies in the exploration of concurrent programs based on the idea that two interleavings can be considered equivalent if one can be obtained from the other by swapping adjacent, independent execution steps. This talk will overview recent context-sensitive, constrained, dynamic POR techniques incorporated in the SYCO system, a SYstematic testing tool for COncurrent programs. We will also describe recent applications of SYCO to verify Software-Defined Networks.