Yes, but i dont think apple will force to adapt the dark mode, as you can see whatsapp has given support for dark mode now, after this long..so its clear that it takes time and apple knows it..
so no need to worry..if your app doesnt support dark mode its ok..you are good with plist solution..and if apple wants the devs to support dark mode they will inform us then we can work on it as we wont have any option left..