Bug Fixes
=========

 * In cases where an MPP payment is claimed while one channel is waiting on a
   counterparty's `revoke_and_ack` message and the `revoke_and_ack` message is
   received prior to the asynchronous completion of the MPP-claim
   `ChannelMonitorUpdate`, the channel will no longer hang (#4236).
 * Deserializing invalid `Duration`s can no longer panic (#4172).