I've just updated to the latest and greatest Visual Studio 15.5 and also got my Boost develop branch up-to-date. But I'm still getting this message: "Info: Boost.Config is older than your compiler version - probably nothing bad will happen - but you may wish to look for an updated Boost version. Define BOOST_CONFIG_SUPPRESS_OUTDATED_MESSAGE to suppress this message." I've just rebuilt my library files that have the new -x64- x32 in the name (great - but grrrr because I have had to change all my command files to generate them, previously in /x64 and /win32 folders ;-) The library files have names like libboost_chrono-vc141-mt-x64-1_66.lib so version number is still at 1.66 (a fact confirmed by the config_info Boost version 106600) The config_info.txt output is attached. So I am surprised to get this potentially useful warning. It would *much* more helpful if the warning told which version number of both compiler and Boost? (Just like the 'File not found' message that provokes "Which *&%$%^!!ing file" expletives). Paul PS The Good news is that defining BOOST_CONFIG_SUPPRESS_OUTDATED_MESSAGE quiets as promised. --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830