The last public version (v0.8.107) offers a set of MIDI routing options (in the Routing submenu of the MIDI section), including DIN Thru.
When this option is enabled, everything on the DIN MIDI input port will be copied as-is to the DIN MIDI output port, with the lowest latency possible.
However, as this could result in MIDI messages being interleaved if several things merge onto the DIN MIDI output, the v1.0 beta offers an additional Safe merge option that ensures all MIDI messages are output without any possible garbling/interleaving.