The Walgreen Co. is keeping its eye on the mobile ball.

Kartik Subramanian, director of mobile product, API and innovation, explained how the retailer is keeping up with the mobile demands of its customers at the 2016 Internet Retailer Conference and Exhibition this week.

“Mobile is the linchpin of our digital strategy,” Subramanian said.

Two years ago, Walgreens piloted beacons at 10 of its New York-based Duane Reade chain of drugstores. Beacons are small wireless transmitters that can sense a smartphone’s location via Bluetooth low energy and send marketing messages and other alerts to consumers’ smartphones.

The retailer has about two to three beacons per store, Subramanian told Mobile Strategies 360 at IRCE. The beacons send out promotions and coupons to consumers who have the Duane Reade iPhone app, and have also opted in to push notifications.

Subramanian would not disclose how many consumers have opted into the beacon-sent messages and are interacting with them, only that the retailer is excited about the number. Nor would he would say if Walgreens is going to expand the beacon program.

Some of the challenges Walgreens learned during the pilot is how to manage beacons remotely, how to make consumers aware of the technology and how to train its store associates about the program, he said.

“It’s important that any small change be coupled with training,” he said.

The Walgreens app also helps the retailer market to its customers. Walgreens has all of its 8,000-plus physical locations geofenced, or digitally fenced. This means if a consumer with the iOS or Android Walgreens app walks into the store, Walgreens will know that consumer is actually in the store.

“We will know when you are around the store and when you walk in,” Subramanian said. “I know this might sound a little creepy, but it has the best intentions in mind.”

If the consumer has opted into push notifications she will receive a smartphone alert asking her if she wants to set her app to “in-store mode,” he said. The in-store mode puts that shopper’s loyalty points at the top of the screen, as well as an in-store product finder search bar that shows a shopper if a product is in that store.  These are the features a shopper would need most in a store, and while they are still in the standard app the in-store mode prioritizes these features.  “It’s the same content just packaged differently,” Subramanian said.

Subramanian also discussed Walgreens’ Apple Watch features, such as having a reminder for a consumer to take his prescription medication.