So, this is interesting:
http://themusics.co/promo-only/promo-only-modern-rock-radio-06-june-2015/The .mp3 of "SFS (Radio Mix)" here, when uploaded to iTunes Match, does not find a "Match" - meaning, theoretically, this is a different track than the album version. I only listened to it once, through my laptop speakers, and didn't immediately notice any difference.
On the July 13th episode of the Hamish and Andy Show,
http://www.hamishandandy.com/listen/2/, Bono suggests that the new (radio?) mix of "SFS" is virtually unchanged, despite The Edge taking great pride in the "new" mix... There is plenty of laughter to accompany this exchange.
UPDATE: After several side-by-side listens through of the album version and the "Radio Mix" in the link above, I
think I detect everso subtle distinctions in The Edge's background vocals - really, a volume discrepancy, only. At 2:18 - 2:19, The Edge's line, "
...and there is a light..." is
slightly louder and more pronounced on the Radio Mix than on the album version. This isn't the only (minor) difference, but it's the most convincing.
What do you think?
(apologies if linking above violates any rules - Moderator(s), please feel free to remove.)