DALLAS – Free Slurpees alone may no longer be enough to increase foot traffic, so 7-Eleven plans to boost its odds of luring tech-savvy consumers into the store for its 87th birthday celebration. The chain will once again give away millions of free 12-ounce Slurpees today, but this year’s freebie celebration will expand into the following week, with everything from free ice cream bars to free cookies to free Big Gulps — for those who download the 7-Eleven app.

"This is about putting convenience at the fingertips of our customers," Laura Gordon, vice president of marketing and brand communication at 7-Eleven, told USA Today. She says that its customers are way above average in smartphone usage.

7-Eleven customers also are way into free stuff. For 12 years, they've shown up by the millions for free Slurpees every July 11, the date that the nation's largest convenience store chain has adopted as its birthday.

But to gain buzz from Millennial shoppers, 7-Eleven is pushing the promotion onto smartphones by requiring folks to download the 7-Eleven app to keep receiving freebies after today.

The goal is not only to build long-term relationships but to boost short-term sales. 7-Eleven will push its Big Bite hot dogs for $1 on Friday (usually $1.99) to wash down with the free Slurpees. Executives also hope to get consumers familiar with the new Doritos Loaded snacks. There also are two new Slurpee offerings this summer: 7-Eleven Lemonade Slurpee (made with real fruit juice) and the Slurpee Lite Sugar-Free Fanta Watermelon Punch.

It will surely be 7-Eleven's biggest day of the year in customer count and among its biggest in sales, Gordon told USA Today. "We'll serve more people on this day than any other day," she says.