Sorry to bump this thread after a long time. I checked back and noticed the forwards compatibility suggestion didn’t make it into the MA 2017 proposal.
That’s a shame – I think some guarantees about forwards compatibility would be really valuable from a data use perspective.
To continue Bill’s TV analogy above: let’s say a publisher is a TV broadcaster, transmitting a black-and-white signal. Maybe the publisher won’t upgrade immediately after the version upgrade to colour. Backwards compatibility means users can still watch their black-and-white channel, even on a colour TV. That’s why backwards compatibility is good – it benefits both publishers and users.
Now let’s say an aid management system is a black-and-white TV. Maybe it won’t be upgraded immediately after the version upgrade to colour. Forwards compatibility guarantees it still works after broadcasters upgrade to colour. Without forwards compatibility, it might just show static noise. That’s why forwards compatibility is good – it specifically benefits users.