Please help me. I need gambas3-gb-qt4-webkit (>=3.8) very badly! It is required by Estru3D software for installation. I have installed gambas3-gb-qt5-webkit_3.8.4-2ubuntu3_amd64, but Estru3d won't recognize it at all!! I can't find that file anywhere!
Go into Ubuntu's "Software Sources" options and check the box to enable the "xenial-proposed" or "proposed software updates" repository. (version 3.8.4-2ubuntu2 of the package should be available in there)
Then open a terminal and run
Let us know if that works or if you have further questions.