NHK report: https://www3.nhk.or.jp/nhkworld/en/news/20240702_18/
BOJ site with samples of all: https://www.boj.or.jp/en/note_tfjgs/note/valid/issue.htm
According to surveys 90% of ATMs and other banking machines are ready for them, while 80-90% of train and bus ticket machines are, 50% of ticket machines in restaurants are, and 20-30% of drink vending machines are.
You will be able to exchange your existing notes at banks.
Enjoy hunting for them!
by Hazzat