[taejo]

German, a European language that has been more or less standardized for several centuries, with a Latin-based alphabet, added a new letter (ẞ) to its alphabet in 2017. As long as that continues to happen, Unicode will have to add new characters, even if no more ancient scripts are discovered and no new writing systems are developed for currently unwritten languages.

[msla]

https://en.wikipedia.org/wiki/Capital_%E1%BA%9E

That letter, the capital eszett, has existed in German typefaces since at least 1905:

> Historical typefaces offering a capitalized eszett mostly date to the time between 1905 and 1930. The first known typefaces to include capital eszett were produced by the Schelter & Giesecke foundry in Leipzig, in 1905/06. Schelter & Giesecke at the time widely advocated the use of this type, but its use remained very limited.

Eszett is usually just a lower-case form; it is most often upper-cased to SS, or two capital letter esses, being an example of how changing case does not always preserve the number of letters in a text. Capital eszett is very rare, but it was in uncommon usage in German text, and so it was added to Unicode.

[tasogare]

Small precision for those who don't know the context: the Eszett (which comes from the ligature of 'ss') existed for centuries already in German writing. 2017 is just the date of its official integration in the alphabet, so it's not a 'new' letter created from scratch. I say that because I remember learning it at school a few decades ago (even if at the time we were warned the subject was touchy), and I was surprised it wasn't standardized that earlier.

[Sukram21]

The Eszett (ß) has been already standardized for several decades (since 1986: with ISO 8859-1 aka latin-1).

The newly added letter is the "capital letter Eszett", which did not exist until recently. One could argue that this new letter is not really needed, as Eszett does not appear in capitalized form except when a word is in all-caps, and was then simply written as "SS".

[jeltz]

The capital version has existed in uncommon use since the early 1900s.

[fanf2]

Standardisation was earlier than that :-) ISO-646 is the 7-bit predecessor to the 8-bit ISO-8859. It dates back to the late 1960s. Like 8859, 646 has several variants, such as ISO-646-DE which has ß where ~ is in ascii. (The trigraphs in C are partly to work around transcoding issues between ISO-646 and EBCDIC variants.)

[tasogare]

Thanks for info, I didn't know that.

[publysher]

And some more precision: this is about the uppercase Eszett. The lowercase variant has existed for ages, and before 2017 was officially uppercased into SS or SZ.

[taejo]

It still is officially capitalized to SS under normal circumstances; capital ẞ is an allowed alternative: "Bei Schreibung mit Großbuchstaben schreibt man SS. Daneben ist auch die Verwendung des Großbuchstabens ẞ möglich." (Deutsche Rechtschreibung § 25 E 3)

SZ hasn't officially been an option at least since 1996.

[gumby]

> Eszett (which comes from the ligature of 'ss')

ß is both visually and from its name (‘s’ ‘z’) a ligature of s and z (“Eszett” in English is “ess-zed). An ss ligature would look like a double integral sign. “Sz” seems like a better way to represent that sound, so I don’t know why it morphed into “ss”

Greek has two characters for s, one for use in the middle and one for the ends of words. English lost this in the late 18th or early 19th century (look in the Declaration of Independence for examples). German kept it longer, at least in Fraktur, which included other standard ligatures, even in handwritten text, such as ch, tz et al. The Umlaut mark can also be considered a ligature for E which is how it was originally drawn.

[oprypin]

This is about capital ẞ. Small ß must've been in Unicode from the start.