Tested on Ubuntu 16.04.4 LTS, with v0.9.13 & v0.9.20:
midi-in works fine (correctly passes incoming data to midi-out, audible in midi applicationes)
sending midi messages (using triggers / script / UI) does not work
Log shows that midi controller data is being sent (However does not arrive at midi applications)
So only in the case of iannix receiving midi-in data, iannix is able to push data to midi-out.
I’m not using JACK, but that doesn’t seem to be the issue (if i send a midi-note to iannix, iannix will correctly forward the note to the midi-device as selected in the config-tab)
I remember we had a similar issue few years ago… but for me it was fixed (looks not!). It was related with the device name: on Window or Mac, MIDI device name doesn’t have the ‘:’ like in ‘Midi Through:0’. Do you have an other MIDI device just to test if it’s the cause of the bug?