Japan has announced starting from May 1st, 2019 they are to apply new era, Reiwa. With regard of this news AKB48 member Okada Nana wrote on her SNS account.
"On April 1st, the name for the new era has been decided to be『 Reiwa 』 The period for Mukaichi Mion-GM has started too! And so to refresh my feeling I dyed my hair purple. I'm really happy that my hair color is the same with GM."