Yes, I agree on the "undocumented" differences between versions. Very small but very annoing, like the default security setting in Manager.
Opening a config with the R9 Manager, if it is a R9 system and security is on then OK, if you have security off then it takes a very long time to get the coonfig.
So I keep security on, now I have a pre R9 system and with security on, yes, it takes a very long time to get the config.
Reported that in the field trial. An easy fix for Avaya as the version is discovered before getting the config.
There are other inconsistant issues as well, like opening a 3.1 config with a 8+ Manager will enable to merge things which cannot be merged using a 3.1 manager. Result : unstable system without a reboot.