- Failover pairs now implement 'MAC Affinity' on leases moving from the

- Failover pairs now implement 'MAC Affinity' on leases moving from the
  active to free states.  Leases that belonged to the failover secondary
  are moved to BACKUP state rather than FREE upon exiting EXPIRED state.
  If lease rebalancing must move leases, it tries first to move leases
  that belong to the peer in need.
- The server no longer sends POOLREQ messages unless the pool is severely
  misbalanced in the peer's favor (see 'man dhcpd.conf' for more details).
- Pool rebalance events no longer happen upon successfully allocating a
  lease.  Instead, they happen on a schedule.  See 'man dhcpd.conf' for the
  min-balance and max-balance statements for more information.

  [ISC-Bugs #13308]