Our Withe Paper on
http://www.reactos.org/xhtml/en/dev_whitepaper.html
says
The original target for ReactOS, with regards to
driver and
application compatibility, was Microsoft Windows NT 4.0. Since then,
Microsoft Windows 2000 and Windows XP have been released. Microsoft
Windows 2000 and Windows XP are both descendants of Windows NT. As
such we can gradually shift our compatibility target without worrying
about the architecture changing too much. In fact, internally,
Windows 2000 reports version information as Windows 5.0 and Windows
XP as Windows 5.1. The ReactOS team have decided to maintain Windows
NT 4.0 as the official compatibility target. This is because most of
the resources, articles and books on Windows NT/2000/XP technology
are written for Windows NT 4.0. This does not mean that features
present in later versions of Windows NT based operating systems will
not be implemented in ReactOS.
Since we changed the reported version to Windows 2000, i'd say that is
not true anymore is it ?
We report higher version for application compatibility reasons. It
doesn't mean we're going after every win2k feature :)