Having the Qt Quick module for Qt 5.8 installed, it still cannot be used in QML:

//main.qml
import QtQuick 2.7
import QtQuick.VirtualKeyboard 2.0

Window {
  visible: true
  width: 640
  height: 480
  title: qsTr("Hello World")

  InputPanel {
    active: true
  }
}

qrc:/main.qml:3 module "QtQuick.VirtualKeyboard" is not installed

There's a directory C:\Qt\5.8\msvc2015_64\qml\QtQuick\VirtualKeyboard with qmldir and plugins.qmltypes files in it, and a Styles subdirectory, but there's no qquickvirtualkeyboard{,d}.{dll,pdb} files like in the other modules.I don't know whether that's the reason, but at least it seems odd.