For sure, sending a version for comparison guarantees nothing. But then, nothing can give a guarantee, right? For a “simplest solution” that improves on “nothing at all”, I’d suggest you want to send -both- a hash, and a human-readable string. But let’s start with just the human-readable string:
(1) a human-readable string might be an s-expression, perhaps?
(2) we’re going to want to canonicalize it somehow, so that meaningless differences are erased. E.g. sorting lines, removing whitespace, etc. But this might break human-readability.
(3) So maybe send hash(canon(version-string)), but also send version-string as-is.
Then when the hashes don’t match, you can print the version-string, which has not been canonicalized, so hopefully will be nice and readable.
That’s all I’m saying. And since you can escape all special chars in teh string, that’s two lines, each CRLR-terminated, that each end sends to the other end.
It’s not a great solution. But at least, it’s better than nothing, and involves very little actual work. If I were to do this, I would also add a magic number at the very beginning – a 32-bit network-order integer to version the entire protocol.