Update: Publisher Bandai Namco has confirmed to Polygon that Project CARS has been formally canned:

Despite much perseverance on the Wii U version of Project CARS we will no longer be actively pursuing development on it as the quality does not meet our own high standards nor our intended vision for the title on this platform. We eagerly look forward to any announcement of further hardware from Nintendo but right now Project CARS is simply too much for Wii U despite our very best efforts. Apologies to our Nintendo fans out there that have been waiting for further news on this but have no desire to release a product that isn't at the very least comparable with our highest-rated versions on other platforms. We optimistically look forward therefore to what the future may hold.

Original Story: Slightly Mad Studios has confirmed to Nintendo Life that the Wii U version of Project CARS has been cancelled.

The status of the game had been thrown into doubt by recent developer comments which suggested that the team was experiencing problems porting the incredibly ambitious racer to Nintendo's system. This followed news that the Wii U version would launch later than its siblings.

Studio head Ian Bell then clarified the situation by stating that Project CARS on Wii U was always a "maybe", and that the release was not part of the original crowdfunding pitch. He did, however, end with a statement which suggested that the team would continue to work on the version, but were waiting to see if E3 would bring any hardware announcements from Nintendo - which, as we all know, didn't come.

With E3 now a distant memory, we approached Bell regarding the status of Project CARS on Wii U and received this reply:

The official line is that we're awaiting an announcement from Nintendo on new hardware. As of now pCARS is simply too much for the Wii U.

Project CARS is available now on PS4, Xbox One and PC, and has been a critical and commercial success. The Xbox 360 and PS3 versions were dropped midway through development.

Slightly Mad Studios has recently confirmed that a sequel is now in development.