You can try compiling QtOpcua module using your Qt 5.6 toolkit and toolchain. If that works, then you should be able to deploy it to your device and use it in your project. If it does not work, then find a different board ;-) Or perhaps use linuxdeployqt to create a self-contained package that will shich Qt together with it. I have no idea if this will work on an embedded device - it's definitely not a standard use of this tool.