Hi,
On a related note, is the on-air format for batman_adv reasonably stable at the moment? If thousands of FreedomBoxen[1] were to start using it, what's the likelihood they would all have to upgrade to a new wire format in the near future?
you might want to define "reasonably stable" for your use case to allow us to give you an equally reasonable estimate. However, mesh technology is pretty young and many ideas are flowing around to further improve it. I am sure the formats will change some day.
Regards, Marek