Hi,
The whole point of the wsrep API project is to demonstrate that
replication logic can be completely decoupled from dbms logic. As long
as API matches (provider loads) you can use any version of Galera with
any version of MySQL, MariaDB, PXC or whatever that can load the
provider..
The problem is purely marketing: people don't want fancy details, they
want a "cluster", so it has to be distributed all together.
Regards,
Alex