it seems that it is a highly failure loaded procedure to upgrade from
GMS14/SLES11 to a GMS18/SLES12.
So we adviced to do a fresh install. Where are the traps doing this?

I should use the same FQDN; the same IP-Addr.; the same certificates; ...
What other files I should backup before going to the new GMS?
Trusted application key? Can I export this?
What else?

What happens to the mobile devices? Is there a need to reregister or