The oldest version of Mickey Mouse will become one of the youngest members of the public domain when the copyrights covering the cartoon rodent’s cinematic debuts expire in the last instant of 2023. While the 1.0 release of Mickey that graced screens in 1928 will become collectively owned on Jan. 1, newer versions of the mouse remain Disney property. And Disney’s continuing trademark for Mickey means you can’t suggest your fanfic is a Disney production or otherwise endorsed by the company.
https://www.pcmag.com/news/get-ready-to-remix-mickey-mouses-10-release-enters-the-public-domain