Operating System: Windows 10
Illustrator Version: 24.1.1

I am trying to add a CMYK graphic to CC Library. When I do, I receive the warning:

"Saving to a legacy format may cause some changes to your text layout and disable some editing features when the document is read back in."

Resetting my preferences did not help. I checked for Adobe updates, but Creative Cloud doesn't indicate there are any available. If I add it as an RGB graphic, I do not get the error. But I need the CMYK version.