They just remastered TSRTS in 2007.
The Song Remains The Same soundtrack album was reissued on CD on 20 November 2007, with the surviving band members having overseen the remixing and remastering of the original release. This coincided with the re-issue of the film, released on HD-DVD, Blu-ray and DVD. The new version of the soundtrack included six songs that were not on the original album release: "Black Dog", "Over the Hills and Far Away", "Misty Mountain Hop", "Since I've Been Loving You", "The Ocean" and "Heartbreaker", plus new liner notes by Cameron Crowe.
https://en.wikipedia.org/wiki/The_Song_Remains_the_Same_(album)#2007_reissue