Ah, too bad that the sequencer mode is being delayed.
For about 20 years now, I'm still holding my breath for a MIDI sequencer that runs on Linux and has all the functionality and user-friendliness of Cakewalk 3 (http://www.vgmpf.com/Wiki/images/6/63/Player_-_Cakewalk_Prof...).
Sekaiju (https://openmidiproject.osdn.jp/index_en.html) is open source and is 95% there in terms of the user interface, but alas it's Windows only and I'm not aware of any effort to make a Linux port. (Don't suggest Wine, because trying to get MIDI to work with that is a nightmare. A nice thing about the current MuseScore is that MIDI playback works out of the box.)