Ten things you might not know about antimatter (2015)(symmetrymagazine.org)
symmetrymagazine.org
Ten things you might not know about antimatter (2015)
https://www.symmetrymagazine.org/article/april-2015/ten-things-you-might-not-know-about-antimatter
https://www.symmetrymagazine.org/article/april-2015/ten-things-you-might-not-know-about-antimatter
Today we know little bit more about antimatter-gravity relation[0][1].
It looks like, matter and antimatter behave in the same way under the influence of gravity. So antimatter does not "fall up".
[0] https://home.cern/news/news/physics/base-breaks-new-ground-m...
[1] https://www.nature.com/articles/s41586-021-04203-w