In this talk, we provide an update on the status of runaway electron (RE) modeling and mitigation for the SPARC tokamak. Many advancements have been made on the modeling front: kinetic simulations of RE distribution functions; 3D nonlinear MHD modeling of thermal and current quench dynamics with both Massive Gas Injection (MGI) and the RE Mitigation Coil (REMC); the addition of REs as a fluid to M3D-C1, along with an investigation of various seed sources; modeling of RE impacts on and their energy deposition in Plasma Facing Components (PFCs); and increased fidelity of synthetic diagnostics. On the engineering side for the REMC, sample testing suggests that the REMC’s alumina-coating insulator has lower voltage stand-off for fast voltage transients with rise times <0.5 ms. An analysis of the disruption Ip-spike shows that the voltage rise time is well below 0.5 ms and that the magnitudes are sufficient to cause punch-through arcing. A resistor in parallel to the REMC switch will reduce these voltages to acceptable levels during normal operations at the expense of allowing REMC currents to flow. However, the error field correction coils will likely be used to cancel the REMC fields during nominal SPARC operations, and analyses are underway to inform this operational mode. Final components for the coil and the 350-kA mechanical switch are under procurement and are expected to arrive in the coming months. Extrapolations to ARC may also be discussed. Supported in part by Commonwealth Fusion Systems.