UPDATE:
343 have released a big update today regarding Halo Wars 2, Halo 5, and especially Halo Wars Definitive Edition. They gave new details on the Halo Wars Definitive Edition:
- Optimized to run natively on Xbox One and Windows 10
- Improved visual effects, graphics and audio
- Up to 4K resolution on Windows 10 PC
- Includes all DLC from the original game
- Brand new achievements
- Bonus Content
Dan Ayoub, who has been working on upcoming title, Halo Wars 2 and came on stage at The Game Awards to show gameplay and came with an announcement. If you pre-order Halo Wars 2 Ultimate Edition digitally you will be able to play Halo Wars Definitive Edition on December 20th.
The description on the page says:
Preorder the Halo Wars 2: Ultimate Edition and receive Halo Wars: Definitive Edition. The codes for Halo Wars: Definitive Edition will be delivered to your Xbox message center 7-10 days from preorder, beginning December 20, 2016.
The next few months will be filled with lots of Halo Wars with the Definitive Edition launching this month, soon the Halo Wars 2 beta on Windows 10 and Xbox One, and the full release on February 17th.
Listing is here