Anticipating a long-awaited yet unexpected reunion is one of life’s more conflicted experiences. Will your old friend look good or awful? Will they be stuck in the past, or a 2.0 or 3.0 version of the person you remember? Most of all, will they still be themselves?

It’s both corny and perfectly fitting to frame ABBA’s first album in nearly 40 years as a reunion with an old friend. One of the most successful and influential groups in the history of the world, their kitschy lyrics and image — two married Swedish couples dressed in matching outfits! — camouflaged the deceptive complexity and sophistication of their music, which smashed chart records globally and turned them into superstars, but also made them a punchline. Yet their reputation and respect grew exponentially in the years after their 1983 split: The music proved surprisingly enduring as the world caught up with its brilliance, and the business savvy of songwriters Benny Andersson and Björn Ulvaeus (who continued to work together) ensured that it remained in the public consciousness, most obviously in the 1994 movie “Muriel’s Wedding” and the ABBA-themed “Mamma Mia!” musical and films.

After decades of the bandmembers playing down any likelihood of a reunion, most fans had given up hope (after all, time waits for no one, least of all vocal cords and waistlines). But three years ago the group — Andersson, Ulvaeus and the peerless singers Agnetha Fältskog and Anni-Frid Lyngstad — announced they had recorded new songs and were preparing some kind of virtual concert experience. Those plans were delayed first by the complexity of the concert and then by the pandemic, but last summer the enterprise roared back to life: Two new

songs followed by a full album called “Voyage” in November! A groundbreaking virtual concert launching at a specially built arena in London in May! Suddenly, ABBA were back in a big way.

The core of this reunion, of course, is the album. What is it about this new music that made the four long-since-divorced members, now all in their 70s, finally take the plunge?

Happily, “Voyage” finds our old friends unmistakably themselves. Andersson and Ulvaeus have said that they made no effort to modernize or contemporize their classic sound based on the current musical climate, and suffice it to say the album backs up that claim: It’s so definitively, timelessly ABBA that it could have come out at any point in the past four decades (and certain moments even feel decades old). They may not be looking for that man after midnight anymore, but the essence remains: delectable melodies, soaring arrangements, sweeping crescendos, dramatic pauses, regal countermelodies, Andersson’s gorgeous piano playing and most significantly, Agnetha and Frida’s singing — the stunning sweet-sour blend that is the single most defining trait of ABBA’s sound. Tempered but strong, their voices have settled into a lower, calmer range, and there’s obviously very little belting — but gloriously, it’s still them, and most of all on the album’s liveliest songs, “No Doubt About It” and “Just a Notion,” which they sing in “Waterloo”-style harmony, with Frida’s tart tone up front.

“Voyage” is bookended by its two strongest songs: “I Still Have Faith in You,” first released in August, a gorgeous, soaring ballad that opens the album with a suitable reunion theme; even more ambitious is the closing “Ode to Freedom,” a swooning, swelling, majestic, orchestral ballad with a Schubert lilt that’s so stately it almost could be some European country’s national anthem.

In between is a combo platter of ABBA styles. “When You Danced With Me” is not a disco anthem but more of a “Riverdance”-type Irish reel; the dainty “Little Things” is a Christmas carol, complete with a children’s chorus. Some are just plain bizarre: “I Can Be That Woman” is like their take on a Tammy Wynette-style epic, with odd, self-excoriating lyrics that start off about a dog, then move on to recapping a troubled relationship (“You say you’ve had it, and you say ‘Screw you’/ I say I love you and I know it’s true.” OK then!).

Certain songs feel like a time capsule — “Keep an Eye on Dan” concludes with a snippet of the piano hook from the group’s 1975 hit “S.O.S.” — and a couple feel time-warped: “Just a Notion” is the kind of ’50s sock-hop pastiche that peppered their early albums, so we’re hearing a ’50s throwback through the lens of a ’70s interpretation, half a century later.

And yes, some moments are extravagantly cheesy: the maudlin lyrics, “Fernando” flutes, synthesizer sounds and guitar solos that make you wonder if they’re kidding. But ’twas ever thus, and let’s be real, ’twouldn’t be ABBA without those things too. Four decades on, ABBA are more ABBA-esque than ever.