Happier Day shows us that they may finally have grown up-or gotten old.

Warning, the newest offering from California punk-poppers Green Day, will probably surprise the band's usual angst-ridden, grunge loving, "everything sucks and that's the way I like it" fans. The group's sixth album, their first since 1997's Nimrod, varies dramatically in its style and presentation.

Now, don't get your baggy pants in a bunch-the same basic Green Day rules apply. One: The album is still full of short, one- or two-word juvenile titles just like the old days (think Dookie and "Brain Stew"). Two: The guitar adheres to the "three chords over and over so all the songs sound the same" rule. Three: Most of the time, lead singer Billie Joe Armstrong seems to be singing in something that sounds like Swahili. Four: You're probably going to like it anyway.

The difference this time is simple yet probably unfathomable to some of Green Day's earlier followers (you know, like us when we were all in high and middle school): They aren't mad anymore! Yeah, it's over. They obviously got all their ya-ya's and their sweaty tears and id-borne rage out last time around, and now they've settled down to attempt a more mature, softer (but not too soft), acoustic sound.

So what made it happen? Frontman Billie Joe is pushing 30-maybe he's growing up. Maybe he's spent the last three years getting in touch with his inner adult. Maybe he's going soft on us. Whatever the case, he borrows the melody from Petula Clark's "Dowtown" on one one track. What's next-a rousing rendition of "Give Peace a Chance?" In a modest attempt to return to his ranting, pissed off ways, the guy does "pledge allegiance to the underworld" ("Minority")-but I'm not buying it.

Overall, despite the change in attitude, this disc is quality. Green Day does at least resurrect the sound of old on occasion. There are a few excellent tracks, including "Macy's Day Parade," a softer, catchy equivalent to the hugely popular and overplayed "Good Riddance" of a few years ago. It may not sound like Green Day, but who cares? The bottom line is, the days of obscenity-laced snarling, references to masturbation and funny names for excrement may never again be seen, and that's probably just fine. What has emerged is every bit as enjoyable. Green Day has grown up-and they still rock.