The other day the official teaser website for New Super Mario Bros. U stated that the game would be running in 1080p. Now the website has been updated to say this:

Experience Mario like never before… in high definition, only on the Wii U console!

They took out the term 1080p for some reason. This could mean that New Super Mario Bros. U may not run in 1080p but instead run in 720p. Maybe someone released the information about the 1080p resolution too quick before Nintendo wanted to release it.