Milestone debuted at #8 on the Oricon Albums Charts, but climbed to the #7 position, taking the weekly ranking of #8.

", but all the videos from the singles;[8] and a type B 2CD edition that contained thirteen tracks on the first disc and Mokudan radio show, which was hosted by the group, and a special booklet.

In the first press limited editions of both type A and B of Milestone, special participation tickets were included to the group's nationwide tour Lead Upturn 2018 ~Milestone~, which began August 5, 2018.

There were two tickets placed in with the first press editions of the album, combined with a "Changing Jacket Set", that included one of three possible versions.

The standard edition contained the title track and the two B-sides "Shampoo Bubble" and "Say Good-bye Say Hello", the first of which were placed on Milestone, as was the image video footage.

There were two tickets placed in with the first press editions of the album, combined with a "Changing Jacket Set", that included one of three possible versions.

It opens with the trio against a backdrop of neon lights, before introducing each member in solo positions.

For the song, the Akira, Shinya and Keita perform the choreography on 21st Century Forest Beach on Okinawa Island.

The video of "Backpack" was uploaded to Pony Canyon's official YouTube on October 10, 2018.