I’m not sure who to properly ask for this, so I’ll default to @JoeKGBX.
How will the new 5th episode (and the full 3D to a smaller extent) be distributed to those who already purchased the Megaton Edition on Steam before it was taken down? Will it be a free upgrade (like the 4th episode was for owners of the vanilla game back in the 90s)? Will it be a discounted paid upgrade? Or will it be that one has to repurchase the entire game again for the couple of new features?