Simple Q: what is the latest OS that will merrily run on an Indigo?

  • Hello; I am new to this, but not to synths in general.
    I am planning to update OS 4.5.1 on my Indigo to either 4.8 or 4.9. 4.8 is listed on the site for "discontinued" synths, which mine is. But 4.9 is listed under modern OS's as suitable for the B which is also what an Indigo is. Soooo... I guess I will go with the latter. I plan to boldly dump everything to computer and then load the OS (4.9?) via USB to MIDI cable. The ultimate goal will be to somehow someday get to new banks E-H. (I guess). BUT Is this the path of woe for a perfectly functional synth? Or will the new sounds make me happy? Or is there little to gain????
    Thanks for your opinions and guidance...