Upshift is a dance-oriented instrumental track by producer s-don, released under the alias Iriss-Frantzz. The song originated from the G2R2018 Climax -GO BACK 2 YOUR ROOTS 2018 Climax- Be-Music Source (BMS) song contest, where it placed 32nd overall in a field of competing BMS entries. Its BMS genre classification is Dance, and the track's driving beat and energetic synth work reflect that label. The song joined the maimai でらっくす UNiVERSE arcade lineup on October 1, 2021, under the GAME & VARIETY category, and later rolled out to Asian and Chinese regional versions in 2022 and 2023 respectively. s-don handled composition, arrangement, and even the BGA visuals for the original G2R2018 release. An extended version titled Upshift (Extend) appears on s-don's album Smashing Time!!, which also includes a remix by fellow producer Yunosuke. Outside of maimai, Upshift has been picked up by other rhythm games including DanceRail3 and Phigros, giving it a modest multi-title presence beyond the BMS scene. In the maimai chart suite, the Expert chart was designed by はっぴー (Happy) and the Master chart by Safata.Hz, with the Master slot earning a 13+ difficulty rating and a 13.9 constant, a demanding chart for its bracket.