[mkayokay]

Duden mentions this: "Bei Verwendung von Großbuchstaben steht traditionellerweise SS für ß. In manchen Schriften gibt es aber auch einen entsprechenden Großbuchstaben; seine Verwendung ist fakultativ ‹§ 25 E3›."

But isn't it also dependent on the available glyphs in the font used? So f.e. it needs to be ensured that U+1E9E exists?

[NoInkling]

According to Wikipedia:

> "Since 2024 the capital ⟨ẞ⟩ is preferred over ⟨SS⟩."

https://en.wikipedia.org/wiki/%C3%9F

Check reference #5 and compare it to the older wording in reference #12.

[Kwpolska]

I don't think there exists any code that makes uppercasing decisions based on the selected font. Besides, if it doesn't exist in the current font, there's probably a fallback font.