This is a preview of the upcoming 3.2 release!
SDL_mixer 3.0 is a complete redesign, rewritten almost from scratch to address deficiencies in SDL_mixer 2.0. The API is completely different and, in our opinion, a significant improvement in power and ease of use. Please refer to README-migration.md for details on how to migrate your program to the new API.
Please let us know if you run into any issues!