Bonus at the Time of Farewell

I thought it was over after evolving to its final form, but there was a comment from Utty saying to wait because there's a thank you gift on the last day. When I opened it the second time, it said '30 days left until farewell' and the message disappeared within seconds of opening the app, but it was there. The Utty comment said: Special bonus being prepared for the final day. Stay with me. I was actually planning to exchange my current Utty for PayPay and quit once it evolved to its final form... But I've decided to postpone it for a month because I want to see it through to the end. I wonder what this special bonus on the final day of farewell will be? I'd love to hear from anyone who has experienced this! (❁ᴗ͈ˬᴗ͈)ﾍﾟｺﾘ