[[!comment format=mdwn
 username="joey"
 subject="""comment 2"""
 date="2017-08-15T19:40:44Z"
 content="""
git-annex could set something in the environment to let the external
special remote know that it supports version 2. Or, git-annex could
reply to "VERSION 2" with a new request to indicate it would
like to use NUL or whatever. That would not break older clients;
they'd reply with "UNSUPPORTED-REQUEST". 

Of these, the environment variable seems cleaner.
"""]]