<snip>Ask Peter Relson about the "long-term stable" message requirements. I guarantee major message changes (unjustified) would be met with fury from the automation community.</snip>
The IBM requirement is to maintain the general "form" of an automatable message so that automation on a message ID will continue to work. If that "form" needs to change, then a different message ID is supposed to be used. Generally, you can add new fill-in choices and you can often add stuff at the end. Peter Relson