Hi nbs,
Direct upgrade from NCM 7.1.1 to 7.3 is not supported when your NCM and NPM are not integrated. You have to go through 7.2, i.e. install 7.2.2 on your Orion/NPM server and point it to the old 7.1.1 DB. Then you must run node sync so that the 7.2.2 installation becoms integrated with NPM. Then you can upgrade to NCM 7.3.
Regards,
Jiri