Version 2.3 of the server will be only available on Linux or Unix. This is due to a dependance that is no more compatible with windows.
At first : why a windows version ? OCS Inventory NG was ported to windows in the past only for test purpose. Production must be done on Linux or Unix (better performance and security).
We will release a new version of the server on windows in future version of OCS (it's on the roadmap) but only for test.