Paul McCartney has released a previously unheard, acoustic version of ‘Calico Skies’ – listen to the track first on NME below.The original ‘Calico Skies’ featured on McCartney’s 1997 album ‘Flaming Pie’ – his second-highest-charting album of the last 25 years.The ‘Calico Skies [‘In The World Tonight’ Campfire Acoustic]’ version features on a new boxset containing unreleased demos, outtakes, and rehearsal tapes from the album’s recording sessions.