Witcher 3 DLC for Xbox Series X?

I've owned The Witcher 3 for Xbox One since the release date, but without the DLC. I recently bought the new Xbox Series X and would love to try The Witcher 3. Since an optimized version that is free for me as the owner and which also includes the DLCs should appear soon, I wonder whether I can now buy the DLCs cheaply for the Xbox One and then get the optimized DLCs for free like the main game. Does anyone have any further information?

If the game receives an update, this also affects the add-ons.

So you don't get the new version for free, but your existing ones will also be patched.