Working with older versions of hg

[Jeremiah Dodds]

Apologies if this is documented somewhere, but I've failed to find any
good info. Is there a list of things to be aware of / careful about
when working with repos you push and pull from that are using older
versions of Mercurial? I work with repos that are primarily accessed
with hg 1.7, and would prefer not to have two versions of hg laying
around. I have current versions on my machines, and so far things have
been going smoothly, but I'd like to avoid any "well, I guess I'll
re-clone that repo" types of situations.