I just recognized, that you still distribute the Galera RPM package
in all of your MariaDB Yum Repositories (I checked 5.5, 10.0, 10.1).
The official Galeracluster Repository http://releases.galeracluster.com/centos already contains galera-3-25.3.20-2 since January 2017.
Is there a reason, why you do not distrubute the newest Galera Package?
We just ran into a Bug with MariaDB-Galera 5.5, which will be fixed with using galera-3-25.3.20-2.
But we are not sure if it is save the install this version or if this might lead to new issues due to incompatibilities.