First official release of Driftfusion. The recent application of lead-halide perovskites as an active layer material in thin film semiconductor devices including solar cells, light emitting diodes (LEDs), and memristors has motivated the development of several new drift-diffusion models that can include the effects of both mobile electronic and ionic charge carriers. Here, we present Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to simulate devices with virtually any number of layers and with up to four charge carrier species (electrons and holes by default plus up to two ionic species). The time-dependent carrier continuity equations are fully-coupled to Poisson’s equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to the material parameters, users have direct access to adapt carrier transport, recombination and generation models as well as the system boundary conditions. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced.