Unicode tells me:

• Special Casing: Lowercase: 00DF [ ‌ß ] Uppercase: 0053 0053 [ ‌S ‌S ] Titlecase: 0053 0073 [ ‌S ‌s ]

• NamesList: = Eszett • German • uppercase is "SS" • in origin a ligature of 017F and 0073 → (greek small letter beta - 03B2) → (latin capital letter sharp s - 1E9E)

(in origin a ligature of 017F and 0073 is not undisputed)

U+1E9E (LATIN CAPITAL LETTER SHARP S ẞ) is not officially allowed in German orthography • NamesList: • lowercase is 00DF → (latin small letter sharp s - 00DF) • Designated in Unicode 5.1