Hi, during the test of boost-1.63 rc 1 some problems occurred (see Marshall's and Stephan's postings). I request to merge my last commits (on branch master) from boost.context and boost.fiber into boost-1.63 (rc 2?) - as well as commit 13f5d9c88ae5363fe547f04c1d272b2a772a8b4d from boost.config. Otherwise the build will fail for gcc-7.1, clang-4.0 and mingw64. best regards, Oliver