We have FNMS 2019 R2 on-premise.
We need Operating System Version in All Inventory tab. However OS Version field is available in NDI file, FNMSInventory Database but can't find it in FNMSCompliance DB. Even can't find it in Report field.
We have recently done some work in the ManageSoft reader which increased the version visibility for different OS names.
You can reach out our support engineer with your current version of Computer.xml attached, we can then send you an updated version, most likely it should work with most of the recent FNMS versions.
Hope this helps,