Modern German is not abandoning ß, ä, ö, ü. Nobody in Germany would write ae, oe, ue instead of ä, ö, ü, exception is if you don't have the possibility to write ä, ö, ü, e.g. because you use a foreign keyboard layout etc. The use of ß was changed some years ago (made (perhaps) mor logical), but still there's many words where you need ß. It's only written "ss" if you cannot use the "ß" letter, same story as for ä, ö, ü.
For those who do not have the letter ß in their keyboards, I tell you a way I found to write it, not so easy, but... well, it's a combination of 5 keys. You can press ALT+0+2+2+3 (0223), this is called like "close s lowercase latin letter". I did not find an uppercase. anyone know? (whether it has I guess). Besides, I think there exists a combination of 3 numbers, but I don't know.