MacOS Server 5.6.3 does not work with Mojave

You could try and contact Apple Support directly ~ as this involves new system software.

• Contact Apple Support //getsupport.apple.com

This URL is a portal for several angles of possible information, but I looked and did not find

any specific macOS Server reference. And I've not used my Late 2012 Mac mini server as

such; while it still has the original Mavericks 10.9(.5) on partition alongside El Cap 10.11.6;

& second HDD w/ two partitions not put to use. ~ And so my 'experience' here is of no help.

• Genius Bar Reservation and Apple Support Options - Apple

Depending on your location and nearby Apple store (or authorized Apple support service

provider) you may be able to arrange to take the Mac mini for help w/ 'genius' or specialist

for hands-on assistance.

PierreJJA wrote:

I upgraded to Mojave and tried to start the MacOS Server version 5.6.3. I get the message that this is not possible because the server version is not compatible with the OS. I removed the server app and tried to download a new version of the server. The message I get is that the OS is too new for this version of the server. So, now what?

Restore your machine to its previous state from your Time Machine or

clone backup and wait until or even if Apple does anything to make

the Server Mojave compatible.