[tor-relays] What to change for v0.2.5.x?

[Steve Snyder]

So now Tor v0.2.5.x Release Candidates are available.  Can someone give 
an overview of what's new for those who don't follow the development 
process?

What can/or should be changed in a working v0.2.4.x relay config to 
accommodate the changes made in the new code?

Are there particular areas (IPv6, multi-threading, etc.) that one should 
be aware of when moving from v0.2.4 to v0.2.5?

The changelogs do a great job of describing the changes between point 
releases but are somewhat overwhelming when attempting to  determine the 
differences between major releases.  If would be great if someone could 
give a brief(-ish) description of those changes.

Thanks.