안녕, 안녕! [Song Credit] Lyrics by 123 Composed by 123, 김준형 Arranged by 김준형 Vocal 123 Guitar 김준형 Bass 김준형 Drums 김준형 Piano 김준형 Strings Arrangement 김준형 Fx 김준형 Mixed, Mastered by STRADA [Credit] Executive Producer UNDFND @official_undfnd Producer TKO, Elapse Marketing Planning TKO Promotion & Marketing Jeonga Oh A&R Seungyong Beag Administration Director Byungwon Kang Cover Art lildeezy Presented by UNDFND