Popular music fans never got a chance to hear how punk rock music of the 1970s and ‘80s would have sounded had it gotten a chance to grow up.

The Sex Pistols and The Clash imploded after just a few years and The Ramones never changed.

But those who, in the 2000s and 2010s, were fans of pop-punk music, that fast-paced, poppy genre filled with ephemeral moments of devil-may-care youth themes, saw precisely how their music has endured, and matured, in a show by chart-topping Maryland band All Time Low.

Nearly 20 years past the release of its platinum major-label debut album, with members now in their late 30s, All Time Low presented a concert Sept. 5 on the Service Electric Grandstand Stage at The Great Allentown Fair that not only reminded how good its older music is, but made it still connect with a crowd that also has matured, and gave them solid new music, as well.

That was evident from the start, as the 19-song, one-hour-and-25-minute set started with “Suckerpunch,” a single from All Time Low’s latest disc, 2025’s “Everyone’s Talking!”

Hooky, more rock, and more adult-oriented, the song nevertheless was still pop-punk, and the crowd, looking to be perhaps above 3,000, most of them crowded into the pit in front of the stage, immediately bought in, clapping their hands above their heads to the beat.

All Time Low juxtaposed that with its platinum hit “Weightless,” which took the audience back to 2009, immediately singing along and loudly cheering.

And that was the theme of the concert: The newer songs, such as the 2021 single “PMA,” are hooky pop-punk, but sounded more evolved, even “adult.” The crowd appeared to understand, jumping, dancing and thrusting their arms, and cheering.

While the hits got the best reaction, the crowd from the start was loudly singing along on 2009’s gold “Damned If I Do Ya (Damned If I Don’t),” those songs sounded as if they had aged like wine, seeming richer and more nuanced.

Part of the reason was lead singer Alex Gaskarth’s voice, which not only has held up well, but in ways has perhaps gotten better with age. So when the band played newer singles such as 2017’s “Dark Side of Your Room,” still catchy pop-punk, or 2025’s “Falling for Strangers,” they sounded like, well, an older, mature version of All Time Low.

That meant the songs were uniformly good: the 2011 single “Time-Bomb” at a thundering volume, 2013’s “Backseat Serenade” with Gaskarth’s voice especially powerful, as he stood, wide-stanced, strumming his guitar.

Meanwhile, the 2020 single “Sleeping In,” while fast, furious and pure pop-punk as it tumbled forward, also has a more mature sound.

It was seven songs into the concert before Gaskarth really addressed the crowd, telling them, “We’ve played here quite a few times.”

The band played the former Allentown club Crocodile Rock Cafe at least seven times, starting in 2007.

“We played Allentown when we first got into our van. How’ve you been? It’s been awhile,” Gaskarth said.

During that time, All Time Low clearly has had a resurgence, starting with its 2020 gold hit “Monsters” with Blackbear and Demi Lovato.

Perhaps that’s why the Allentown audience looked to be twice the size of the crowd when All Time Low last played the Lehigh Valley and, on a twin bill with Dashboard Confessional at Bethlehem’s Musikfest, drew just 1,500, among the festival’s smallest ever for a headliner.

One of the group’s last hits before that lull, 2015’s “Something’s Gotta Give,” still resonated and didn’t sound dated. Gaskarth added the lyrics, “And Allentown is singing along” ... and the crowd was, and waving its hands, 10 songs into the show.

The 2025 single “The Weather” actually was better. It still fit in perfectly pop-punk, but seemingly from an older perspective.

Gaskarth played the 2007 gold hit “Remembering Sunday” alone on acoustic guitar, slow and intense, with the crowd swaying. It again drew attention to how good his voice remains, hitting high and expressive notes.

He also started the 2016 slower and lighter single “Missing You” on acoustic before the full band returned.

The mixing of eras continued with the fan-favorite minor hit “Lost in Stereo,” followed by the 2020 minor hit “Sleepwalking,” to which the crowd also sang along. “You sound amazing,” he told them.

Perhaps even better was “Hate This Song,” the 2024 single with rockers I Prevail, which was more rock-punk.

The main set closed with the aforementioned “Monsters,” with the crowd again singing along, and Gaskath still displaying great energy.

The encore opened with “Little Bit,” another song from “Everybody’s Talking,” and it was pretty good.

The band closed with its biggest hit, 2008’s four-times-platinum “Dear Maria, Count Me In.”

The crowd’s reaction showed that pop-punk not only has endured, it has matured.

The opening act was Los Angeles-based trio Kiss The Scientist, playing what lead singer Max Tomack said was the band’s first-ever concert on the East Coast.

The band also showed that new pop-punk also still is alive.

While its eight-song, 30-minute set also touched on screamo on songs “Smile” and “Afterglow,” which the crowd cheered, emo (its new single “Life You Want”) and rock, its best were pop-punk.

The speedy “Lightweight” was good, the set-closing “I Gave YouTen Dollars to Buy Pringles, But You Didn’t Give Me Change Back (Pringles Aren’t $10)” even better, and the opening song “High” was pop-punk that might have been a hit in the 2000s.