[3] The group's final single with Seohyun, titled "Forever", was released posthumously on January 20, 2009.

[5] On August 17, the group made their return with the song "Ask," released as part of the OST for the Korean series Protect the Boss.

[6] In September 2011, the group released their reunion song "Loosen the Necktie", which charted #84 on Billboard's "Korea K-pop Hot 100.

"[7][8] While promoting the single, the group began performing in Japan for the first time in their career.

[11] In May 2019, the group returned with single Endless Way, featuring the surviving members of the original lineup.