Seventeen's Woozi released a new track on January 26 at midnight KST.

On this day, Woozi officially released his solo track "What Kind of Future" on ASTRO member Moonbin's birthday, keeping his promise to Moonbin.

Woozi had previously shared the unreleased song 'What Kind of Future' with fans, emphasizing its personal significance to him. After Moonbin, who had also listened to the song, expressed his deep appreciation for it, Woozi promised to release the track as a special gift on Moonbin's birthday.

As Woozi promised, he released the song on January 26, celebrating Moonbin's 26th birthday.

Woozi previously dedicated a letter to Moonbin and wrote:

"My Moonbin, I miss you a lot. It seems like just a week ago that we said we would make time to dance together and you told me I'm number 1 no matter what. I vividly remember you, with an unusually bright smile, declaring that I was definitely the best. Isn't this world harsh? Haha. I truly wonder why such a cool person like you liked someone like me.

I'm sorry for being so awkward and shy, unable to express myself well. You were truly an amazing younger brother. I feel embarrassed for not being able to say more positive things to you, considering all the good things you shared with me.

I feel so ashamed for not properly expressing myself. Bin, you gave me so much strength. You always recognized and appreciated my music and dance, giving me constant support and anticipation. I pretended to brush it off lightly due to shyness, but do you know how good it felt? Haha, confessing it now.

I think there won't be another younger brother who likes me as much as you do, and there probably won't be in the future. That's why my feelings of cherishing and valuing you grow even stronger, and I don't know what to do. Haha.

'What Kind of Future' that you always kept asking when I would release it, I'll make sure to release it on your birthday, even if I have to fight with the company. I already finished the Bibimmyeon you got me. You should've given me a chance to give you a birthday gift too, you're so bad!

I'm sorry that this is the only thing I can do for you. I love you, cherish you, and thank you. You will always remain the coolest and most appreciated younger brother in my heart. Let's be happy. I love you, Bin."

Korean netizens commented, "Bin happy birthday," "This is making me so sad," "Woozi kept his promise," "The song sounds so sad," "Everyone, be happy in the future," "Moonbin happy birthday, we miss you," "This is so touching," "This is making me cry," and "Moonbin really liked this song and Woozi released it on his birthday."