I am replacing the first primary server with the second primary server.
Everthing is working and seems ok.
only

I've done the following export Certificate Autority from the first primary server
Replace it on the second primary server.
Closest server dafault rule changed placed the second primary server at the top. ( Collection Server content Servers and Configuration servers )
Refresh my servers and devices so the get the new Closest server dafault rule
After thar i retire the first primary server and uninstall this server.

Everthing works fine but when i look at the existing clients.
It shows

ZENworks Server Properties
Property Value
Management Zone: TEST
Server DNS: Server.local
Server Address: 172.16.15.59

This are the setting of the old first primary server that not exits any more.
strange, everything works properly

When i deploy a new client

ZENworks Server Properties
Property Value
Management Zone: TEST
Server DNS: Server1.local
Server Address: 172.16.15.60
This are the right settings of the replaced server.