On March 18, 2026, ZEROBASEONE posted a new update on Instagram. Set against a blue mailbox with beautiful flowers, the post carried the caption "𝘁𝗼_𝗭𝗘𝗥𝗢𝗦𝗘." The letter shown in the images was filled with gratitude and affection for fans. Opening with "Forever unchanging love for you," it conveyed the group's sincere feelings. Touched by the message, fans reacted by saying they felt "happy."