Center City Sips, the summertime neighborhood happy hour created to draw people out after work with the promise of discounted drinks, turns 15 this year. Old enough that organizers decided to give the annual event some touch-ups.

When Sips launches Wednesday, with a roster of 90 participating bars and restaurants, it will come with drinks that cost a dollar more than last year and a campaign featuring vintage-style images intended to convey elegance and class. Organizers hope the rebranding will draw the attention of customers looking for a more intimate experience from Sips, which in recent years some have associated with teeming crowds at large outdoor beer gardens.

"People think about the large outdoor venues that are so popular, and they might think that's not for them," said Michelle Shannon, vice president of marketing and communications for the Center City District organization. "But there are dozens and dozens of cool little places, and we want to remind people of that."

Shannon cited places like the Balcony Bar at the Kimmel Center, where people can sip drinks while overlooking Broad Street. There's the unassuming Las Vegas Lounge on Chestnut Street, the date-night spot Charlie Was a Sinner, and  the sleek 1225 Raw Sushi & Sake Lounge, which offers Gyoza, shumai, and rolls for just a few dollars.

With $6 cocktails, $5 wine, $4 beer, and half-price appetizers, Sips drinks are still well below many happy hour prices. (Though Center City District has raised Restaurant Week prices over the years, Shannon said this was the first time they have been raised for Sips.) Some restaurants also offer discounts on food for guests who stay for dinner, and the CCD also partnered with museums to offer discounted admission on Sips nights this summer.

The growing popularity of Sips has led to crowds at some of the city's outdoor venues. Last year, a minor but well-publicized brawl at the Comcast Center plaza led the Chops restaurant on the site to drop out of the promotion for the summer. CCD will pay for additional security patrols near the city's largest venues, Shannon said.

This summer, Chops is back in, though SkyGarten, the 51st-floor beer garden in the heart of Sips territory at 17th and Arch, has opted out. There are several Stephen Starr restaurants in the midst of other Sips spots, such as El Rey and the Continental Midtown, but none are on the list of participating restaurants. The popular Irish bar Fado is not on the list, nor is the Happy Rooster at 16th and Sansom.

Sips has been a powerful moneymaker for the participating restaurants, Shannon said, but some owners decline because it doesn't fit their marketing goals, or they're not interested in offering drinks at such a steep discount. Other restaurants,  such as El Rey, which offers dollar tacos and $4 margaritas every weeknight, already do brisk business during happy hour.

"For many of our bars and restaurants, it used to be slower during the summer season," Shannon said. "Sips has been a real boon for these establishments. At the same time, it's important to remind people that this is an event intended for young professionals who want to relax after work."