Vectorworks Inc is currently testing the compatibility of Vectorworks 2018 with the public release of Mac OS 10.13 High Sierra.
Because the new version of Vectorworks is released before the next Mac OS is officially released to the public, official Vectorworks support for the new Mac OS cannot be established before the public version of the new Mac OS is released. Vectorworks Inc is currently testing and working on compatibility of VW2018 (and VW2017) and Mac OS High Sierra.
As of September 26, 2017, the official statement from Vectorworks Inc about Mac OS High Sierra can be found here.
We highly advise that you do not upgrade your mission critical Macs to High Sierra until Vectorworks Inc can fully confirm Vectorworks 2018's compatibility.
An operating system compatibility chart can be found here.