The 65-year-old singer has shared an updated about the group's currently untitled follow-up to 2017's Songs of Experience and cryptically explained it was important for the One hitmakers to "deal with the past" before moving forward.
Asked about the new album, he told Rolling Stone magazine: "Nostalgia is not to be tolerated for too long, but sometimes you've got to deal with the past in order to get to the future and to the present. To get back to now is our desire. Get back to this moment we're in.
"We've been recording. And it sounds like future to me. We had to go through some stuff, and we're at the other end of it."
Drummer Larry Mullen Jr missed the group's U2:UV Achtung Baby Live at Sphere 40-date Las Vegas residency after undergoing neck surgery but Bono praised his recovery and how he is back better than ever.
He said: "We've been playing in the room together, the four of us.
"And I can tell you (Mullen Jr) is completely through whatever storm of injury he's been through. His playing is at its most innovative. He's just all about the band. He doesn't want to talk about anything else, which is kind of amazing.
"By the way, being a band in a room where each individual musician has a role that's singular and collective is so rare because music is assembled these days.
"And even some of our music we have assembled, and we'll do that again, but to try and capture a moment of a rock 'n' roll band in full flight is at the heart of this record that we're making that we've recorded, but we are not finished."
The Vertigo singer - who admitted he doesn't know when the album will be released - was also quizzed on the possibility of a special box set to mark the 30th anniversary of U2's album Pop.
He replied: "Well, I never thought about that. Actually, I'm sure somebody clever has thought of that. But if they haven't, I'm not aware of it.
"And the film of the PopMart tour in Mexico is one of the most extraordinary U2 shows ever. I love the imagery around that album. And the only thing that album wasn't was pop."
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