The original game will be remade in Unreal Engine 5.
The Witcher Remake

CD Projekt Red announces that they are working on a full remake of the original Witcher game. The studio says that this is the game that was previously known internally as "Canis Majoris." They will be working with Fool's Theory on this and will be built from the ground up using both Unreal Engine 5 and the toolset CD Projekt Red is creating for use with the new Witcher saga.

Today's announcement says that the project is in the early stages of development at Fool's Theory. Fool's Theory helped as a support studio on games like Divinity Original Sin 2, Baldur's Gate 3, and Outriders. This studio is made up of industry veterans that also helped work on The Witcher 2: Assassins of Kings and even The Witcher 3: Wild Hunt. It sounds as though CDPR's role will be providing creative supervision.

“The Witcher is where it all started for us, for CD PROJEKT RED. It was the first game we made, ever, and it was a big moment for us then. Going back to this place and updating the game for the next generation of gamers to experience it is just as big, if not bigger,” said Adam Badowski, Head of Studio, CD PROJEKT RED. “Collaborating with Fool’s Theory on the project is just as exciting, as some of the people there have been previously involved in The Witcher games. They know the source material well, they know how much gamers have been looking forward to seeing the remake happen, and they know how to make incredible and ambitious games. And although it will take some time before we’re ready to share more about and from the game, I know it’ll be worth the wait.”

"I am very happy that my professional paths have crossed again with fellow developers from the time of working together on The Witcher 2 and The Witcher 3. Especially when it's a remake of a project that is so close to our hearts,” said Jakub Rokosz, CEO, Fool’s Theory. ”We are excited to join forces with CD PROJEKT RED, and our goal is to give players another great game from the iconic Witcher series."
With this game being announced now and still being so early in development, it's still probably a decent amount of time away from being released. Still, we will keep you up to date on any progress as it is revealed.

Also, platforms for this remake also weren't yet announced. However, it's probably easy to assume that this will be for PC along with the newer consoles like PlayStation 5 and Xbox Series X|S.