Tested last 2.1.9_pre in GTK version and there is no problem with this GTK version.
Looked a bit around to see if i could replace the Qt dll’s that come with G’mic in version 5.8.0.0 and simply replace them with newer versions like 5.9 or 5.10 but there is loads of files at https://download.qt.io/official_releases/qt/5.10/ and not sure if there is what i need there ( most files need to be compiled it seems ).
Well not even sure if G’mic would work after simply replacing the Qt5Core, Qt5Gui, Qt5Network, Qt5Widgets dll’s with more recent versions of those dll’s or if needs to be compiled directly with those to work ( I’m not a compil’ guy 
)