Brian Niccol wants to give Starbucks’s operations a caffeinated jolt.

Roughly five months into his tenure running the world’s largest coffee chain, Niccol is spearheading changes to overhaul the business and improve the brand’s perception with consumers. Niccol recently told The Wall Street Journal during an interview that fixing ineffective mobile ordering systems is his biggest challenge in turning around Starbucks in the U.S., and one of the greatest opportunities for improvement.