can you please try to reinstall the client from MyStandard or www.standardinstall.com? As you mentioned maybe it's related to MacOS client issue: https://partners.hansaworld.com/forum/viewmessage/13/3376
This is not the issue of upgrade SERP. But serverip.dat in this case contains the value: 192.168.88.12:1301, so this is local IP of the server with SERP.
Anyway I don't understand what do you me...