3.9.1 (unstable): * Change ABI name to libxml++-4.0 There is also a libxml++-3-2 branch for the libxml++-3.0 ABI, which still uses glibmm-2.4. * Build: - Use glibmm-2.62 instead of glibmm-2.42. - Require C++17. * Parser: Make some methods const