[tor-relays] Guidance on 0.2.2-to-0.2.3 migration?

Attention Tor developers: Now that v0.2.3 is at Release Candidate status, can we get get some guidance for those relay operators that have not kept up with development? What changes can/should be made to a working v0.2.2 torrc for best 0.2.3 operation? What are the major changes (SMP? IPv6? memory/CPU requirements?) that should be considered when establishing a new relay? Thanks.