I thought the German language deprecated the use of ß years ago, no? I learned German for a year and that's what the teacher told us, but maybe it's not the whole story
Se fareblus oni, jam farintus oni. (It definitely won't happen on an echo-change day like today, either. ;))
Contra my comrade's comment, Esperanto orthography is firmly European, and so retains European-style casing distinctions; every sound thus still has two letters -- or at least two codepoints.
(There aren't any eszettesque bigraphs, but that's not saying much.)
The lowercase of "DON'T FUSS ABOUT FUSSBALL" is "don't fuss about fußball". Unless you're in Switzerland.
[1] https://en.wikipedia.org/wiki/Code-switching