Released on 7 February 2021 as the fourth single.
Recorded in 2020 in Berlin, Germany, "Nostalgic blue" is a departure from the sound of their previous single "Time travel", and incorporates a lighter pop rock sound, while being described as "sweet" and "sugary".
"Time travel" was released on 25 January 2020 as the third single. This song received acclaim from music critics with lyrical content.

The single achieved moderate commercial success, ranking within the top 20 of Billboard’s Hot Rock Songs.
"Collapse" is the second single and it was released on 5 December 2019. The song peaked on the Billboard Hot 100 at No. 15 making it the band’s highest-charting single.
Collapse is considered the band’s "breakthrough" hit and is crediting with introducing the band to a mainstream audience.
Released on 14 August 2019 as our debut single.
It failed to chart the Billboard Hot 100, however, it peaked at No. 38 on the Billboard Hot Digital Songs chart.
The song features instrumentation from a "happy" xylophone and a "rubbery" bass guitar.