The Boost SC suggested I ask about Microsoft Windows XP support in Boost libraries here, so I'd appreciate if library maintainers could state: 1. If they still support Microsoft Windows XP i.e. actively do not use APIs not supported by XP. And if SP3 is the only service pack supported, or if any XP is okay. 2. Whether they regularly test their libraries on a Windows XP machine to ensure their libraries work there. 3. Their personal opinion about when would be best to drop mandatory Microsoft Windows XP support. Individual library maintainers can of course choose to keep supporting it. As we all know, Microsoft Windows XP is no longer supported by Microsoft as of April 2014, however a widely available registry tweak reenables support and updates until 2019. However Visual Studio 2012 cannot run on XP, nor by default can produce binaries which execute on XP, so testing and developing for XP compatibility is going to become increasingly difficult. It may become wise to announce a date that XP support guarantees will be dropped, and any users needing XP support must remain on an older Boost version and/or make use of Boost modularity to mux their own Boost distro. One big reason for thinking about this is that the first C++ 11 mandatory Boost libraries are just around the corner, and they of course need VS2013 or even VS2015 and so therefore cannot promise Windows XP support. There are also a number of post-XP APIs the assumption of which would make some library authors very pleased. For example, I would assume any Boost.Thread v5 would use the Vista only condvar APIs as one can then skip emulating condvars with win32 semaphores which would be an enormous saving of code complexity. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/