It comes in four flavours: a patch that can be applied to the v2.3 sources; full source package (=2.3+patch); precompiled binaries for MSVC6.0 and for the .NET C++ compiler (MSVC7.0) -- the latter two have to be unzipped into an existing 2.3 binary installation. Enjoy!

OMNeT++ 2.3p1 is a bugfix release:
- resolves issues of compiling the package with the Microsoft .NET compiler (aka VC7)
- contains a number of GNED usability improvements and bugfixes (thanks to Eric Wu and Steve Woon for the hints)
- in Tkenv it makes nested message structures (defined in .msg files) visible in inspectors

What it doesn’t contain yet are the new opp_neddoc, new Tkenv features such as senddirect animation, the new parallel simulation architecture, dynamic loading of NED files and other refinements. These features need more testing and will be available in the next release.