The Yamaha AN1x Synthesizer mailing list

My AN200 already had OS v. 1.03 in it when I found the 1.03 update at
a Yamaha website.  If I remember right, Yamaha wouldn't even say
what's different about 1.03. (When asked about "the sequencer bug"
Yamaha at one time was even quoted as saing that the AN/DX 200
operating systems weren't upgradeable via MIDI.)  I think there was
someone here who tried to update to v. 1.03 and ended up ruining their
AN200.  I'm not saying you'd have the same result but if it were me, I
wouldn't bother.  For my $0.02, unless an OS documents offering
something that I'd use or view as an improvement in my synth, then I
won't load it.  e.g. with my Ion, I updated from OS 1.0 to 1.05
without hesitation but I haven't updated to 1.06 because it doesn't
offer anything that is relevant to how I use the Ion.