DAYS is the 12th song covered by Poppin'Party and was originally sung by FLOW.
It was first announced on June 6, 2018, and released in the Japanese official Bang Dream Game server the same year, and also available in all the servers of the game except the Chinese server.
A full version of the cover was later inserted in BanG Dream! Girls Band Party! Cover Collection Vol.2, released on March 16, 2019.