The symbol in question demangles to lime::LimeManager::update(std::function<void (lime::CallbackReturn, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)> const&) However, commit https://gitlab.linphone.org/BC/public/lime/-/commit/51091d1ca0fdd261db9252f47a7d573f43f2fe29 changes this to start with a String. Looking at the git history, this change occured _after_ 5.3.0-alpha was tagged. However, the packaged 5.2.73 tarball already includes this change ! -> lime-5.2.73 is wrong as it already includes an API change meant for 5.3.0