This new version of ejabberd improves the cluster management to make it simpler to use. It fixes issues some may have faced when setting cluster with ejabberd 15.09 and 15.10.
leave_cluster do not depend on external scripts anymore. This makes operation simpler from user perspective and more portable across systems. The commands are supported on Microsoft Windows the same way as on Linux and OSX.
Read the full announcement on ProcessOne blog: https://blog.process-one.net/ejabberd-15-11-simpler-cluster-setup/