Marriott International has overhauled its mobile application to emphasize personalization and guest services, underscoring the fact that millennials are driving companies to put digital natives at the forefront of their software development process. The hotelier has embraced design thinking for the digital era, a key strategy in a competitive industry loaded with choice, including Airbnb and other home-sharing startups.\n"Where you're going to win the game is in the stay itself," says George Corbin, the hotelier's senior vice president of digital. "You can do the best job you can to build a great website and great app for the booking experience but the stay is going to be the arbiter on whether you come back or not."\n Marriott \n(Click for larger image.)\n\nMarriott is playing from a strong position after acquiring Starwood Hotels & Resorts Worldwide last year for $13 billion. As the largest hotel chain worldwide, Marriott now operates 30 brands, including 6,000 hotels and 1.2 million rooms in 110 countries worldwide. Yet the hospitality industry has reached a crucial inflection point as purchasing power from millennials (Generation Y) and later generations is gradually eclipsing that of Generation X and Baby Boomers.\nOur (upwardly) mobile millennials\nCorbin says that many millennials, which Boston Consulting Group says will constitute 50 percent of the U.S. workforce by 2018 and account for half of all travel purchases by 2020, prefer to book travel online or through their smartphone. And whether it's classic rival Hilton Worldwide or new challenger Airbnb, competition remains only a click away, as Corbin and his digital team know full well.\nTo curry favor with millennial travelers, Marriott has personalized its mobile application so that its home screen content changes to reflect a guest's stay journey. A mobile app user with no trips booked will see the booking bar on his or her home screen. But the content gets interesting after you book a stay.\n[ 30 CIOs share their strategic focus ]\nIn the run-up to a trip, the home screen will display any reservations you have made through the app. And the content offerings expand on the day of the trip, with the home screen showing content related to the hotel, including a map and directions, as well as buttons to check-in and make service requests. For example, a simple thumb tap will allow you to request more towels or extra pillows, for that hotel location.\nWhen you check in using the app you can request\u00a0room upgrades\u00a0and receive notification it has been fulfilled before you arrive. The app is currently available for iOS devices; Marriott plans to release an Android version later this year.\nIf the approach sounds like how you would want a hotel app to service you that's by design. Design thinking, or human-centered design, places the user at the heart of product development and meshes it with the potentials of the technology to achieve the desired business outcome. Corbin says Marriott has embraced design thinking as a way to make its mobile app more of a "warm embrace" for guests.\nIdeally, such service-oriented changes will resonate for a guest base that has already proven willing to book Marriott stays through smartphones. In 2016, $1.7 billion of Marriott's $13.4 billion ingross online bookings came through the mobile app, up 70 percent from $1 billion in 2015. And while Marriott mobile app users have historically used the app purely to book travel, Corbin says that two-thirds of the application usage stems from services unrelated to bookings. For example, guests have logged more than 20,000,000 mobile check-in and check-out requests through the mobile app to date.\u00a0\u00a0\n[ Download the State of the CIO 2017 research report ]\n"It used to be about the booking but the lines crossed in 2015 and people started to use the app for more than [the] commerce component," Corbin says. "Based on research on what customers want, we need to make sure we're building out features and services to support them in each of those moments."\n\u2018Alexa, are you spying on me?\u2019\nEventually, those mobile "moments" could extend beyond the app on your phones to your voice, which thanks to the burgeoning success of Amazon.com's Alexa has become a focal point of consumer-oriented companies. Corbin says Marriott, which allocates a small group of employees who focus on emerging technologies, is exploring how voice recognition might work in the context of the guest stay experience.\n[ Related: 10 mobile marketing trends to watch in 2017 ]\nQuestions Corbin is considering: What data sources would such a solution draw from? When a guest checks out, does it clear the record after they are gone? And the big consumer privacy dilemma: How do guests feel about something listening in on them when they're in the room?\nMoreover, issuing service requests from a global hotel chain isn't like using ordering a pizza. Take room service, for example. Ordering a burger sounds straightforward until you get into the permutations, including questions such as these: How do you want that cooked? Cheese or no cheese? What kind of bun? Hold the onion.\n[ Your guide to top tech conferences 2017 ]\nMarriott would have to train the voice assistant to recognize the various vocal patterns and idiosyncrasies associated with human speech. The complexity grows exponentially when you consider the full complement of booking services Marriott offers. "There are a lot of factors that come into play and you've got to figure all that out before you go out at scale," Corbin says. "It's early days but there is tremendous promise."\nAs Marriott explores these options it will lean heavily on data generated from guest feedback, which contributed to the mobile app relaunch. While Marriott relies on web analytics tools and social media, it also checks consumers' pulse through 20,000 in-application survey response a month and application store reviews. And while employees have spirited debates about what they think is cool or what the user would want, the customer-driven metrics win out. "Metrics are our lifeblood," Corbin says. "Our mantra is, 'data over opinion.'"\nWhile digital "owns" the customer experience, including the website and mobile app, employees from both digital and IT are co-located and build software in agile scrum teams. When issues arise, such as the API problem and UX booking path snafu that darkened the mobile app relaunch in February, members of each team tackled the challenge together and rolled out updates over the next several days. There was no finger-pointing, no digital versus IT, Corbin says.\nUltimately, products are developed, fixed and polished with the customer in mind. "The customer is the ultimate arbiter of where we want to focus," Corbin says. "Once you share that with everybody in the organization, people get aligned quickly."