Halo: Spartan Assault will be coming to the Xbox One on the 24th December as a digital download for $14.99.
However if you purchased “Halo: Spartan Assault” for Windows 8 devices or Windows Phone 8 to date or purchase prior to December 15, 2013, will be eligible to purchase the Xbox One version of the game at the discounted price of $4.99.
The deal will be automatically applied if you use the same account to purchase the game on both applications.
Xbox 360 owners will get the same deal when Halo: Spartan Assault launches on that platform next month.
Read more at Xbox Wire here.