Hi, I try to add icu support in boost conan package, but on windows with msvc, the build never use icu. During icu detection in boost.locale, the has_icu.exe never build because configure.builds try to build in debug mode when I use property "variant=release" in b2 command line. I can see that in config.log written by b2 during build : b2 use icuucd.lib and icuind.lib instead of icuuc.lib and icuin.lib. So icu is not correctly detected, and so never used. If I bypass the has_icu test, boost locale build fine and have icu backend as expected. This behaviors only fail builds that use different library in release and debug mode, like icu build with msvc. Is it the correct behaviors ? - If yes this is a bad news for library with different library name in release and debug mode. - If no ... houston, we have a problem Best regards David