The 12.9-inch 2021 iPad Pro unveiled April 20 is slightly thicker than its predecessor. And that’s enough to prevent the latest tablet from being a good fit with the Apple Magic Keyboard released last year. But apparently the fit is just close enough.
Update April 29, 2021: Apple added a paragraph to its support document for this keyboard that says:
“The first generation of the Magic Keyboard (A1998) is functionally compatible with the new iPad Pro 12.9-inch (5th generation) with Liquid Retina XDR display. Due to the slightly thicker dimensions of this new iPad Pro, it’s possible that the Magic Keyboard may not precisely fit when closed, especially when screen protectors are applied.”