From the article below - The copyright that is set to expire is the depiction of Mickey Mouse in his original iteration of the 1928 cartoon Steamboat Willie. Unless the copyright on the character is extended, that version will enter the public domain in January 2024. However, Disney still holds copyrights on other versions of Mickey Mouse.

Open Secrets wrote in March that Disney began its intense lobbying efforts for copyrights in the 1970s, which resulted in Congress passing the Copyright Protection Act of 1976 and later the Copyright Term Extension Act of 1998, which has also been called the "Mickey Mouse Protection Act."

Those laws allowed Disney to extend its copyright on Mickey Mouse until January 1, 2024. However, author A.A. Milne's original 1926 version of the Winnie the Pooh character entered the public domain in January of this year, though Disney still holds the rights for versions of Pooh created after 1926, as well as for Tigger and other Pooh-related characters.