I probably should have done more reading before I asked my question
I cloned a production VM and Upgraded:
iRedmail 0.8.4 -> 0.8.5 -> 0.8.6
iRedADP 1.4.0 -> 1.4.1 -> 1.4.2
iRedAdmin-Pro-MySQL 1.6.0 -> 1.8.1(strips custom rebranding...which is understandable)
roundcubemail 0.8.6 -> 0.9.4 (strips custom rebranding...which is understandable)
In any case, thank you for the help. I no longer require an older iRedadmin version, for the moment. Still more stability/bug checking to do, but at first glance, looks good.