I just tried to install Ardour 6.0 in Debian Sid/Unstable. I get:
WARNING: GCC4/5 libstdc++ ABI Mismatch Ardour was compiled with gcc4, your system uses a newer version of the standard c++ library. Plugins on your system may not load or plugin-UIs may cause crashes.
Should I stick with 5.12? Should I (try to) compile Ardour myself?