The OSVersion element contains the version of the operating system running on the domain controller.
<xs:element name="OSVersion" nillable="true" type="xs:string" />
The OSVersion element is populated from the computer!operatingSystemVersion attribute on the directory server's computer object. The Directory Server's computer object is referenced by the server!serverReference attribute ([MS-ADTS] section 184.108.40.206.220.127.116.11) on the parent of the nTDSDSA object specified by the GetADDomainControllerRequest/NtdsSettingsDN (section 18.104.22.168.2.3) input parameter element. If the server!serverReference attribute is not present or cannot be read due to the client lacking access rights to read the attribute, the server returns the SOAP fault described in section 22.214.171.124.8.1. If the computer!operatingSystemVersion attribute is not present or cannot be read due to the client lacking access rights to read the attribute, the server returns a null ActiveDirectoryDomainController/OSVersion element.