Almost missed this release. A few days ago, the Satellite 6 Maintenance tools were released. These are tools that will ease the migration to Satellite 6.3 once is released, as well as one of my favourite BZs for Satellite: BZ 1480346 Tool to change Satellite hostname
They can be installed with :
subscription-manager repos --enable rhel-7-server-satellite-maintenance-6-rpms yum install rubygem-foreman_maintain satellite-clone
Note the repository above is part of RHEL 7, not Satellite product.
Also bear in mind this is a very first iteration of these tools; I'd expect they will be further enhanced before the Satellite 6.3 GA release. At the moment they are in a BETA state :-)
You can read the official notes here: