Apple Inc. (NASDAQ:AAPL) is expected to preview iOS 7 at WWDC in June, and when it does, it may show off a new “killer app,” according to analysts at Morgan Stanley (NYSE:MS). In a report issued to investors this morning, they see such an app as a possible catalyst for Apple Inc. (NASDAQ:AAPL)’s stock.

iOS 7

One of their theories for the company’s next “killer app” is a digital wallet, which is what Gene Munster predicted earlier this month. However, he doesn’t think we will see the app until sometime in the next year or two. In the view of Morgan Stanley’s Katy Huberty, the digital wallet could drive demand for the iPhone 5S in a way similar to how Siri drove sales of the iPhone 4S.

The analysts said they have met recently with Apple Inc. (NASDAQ:AAPL) management and have come away believing that Internet Software and Services Chief Eddy Cue, is also improving the company’s other Internet-based apps like iCloud and Maps.

They also expect either developers or users could be paying for some of the new services that are in development, which would give the company’s annualized revenue stream a boost and help to monetize its user base more effectively.

The analysts pointed to Apple Inc. (NASDAQ:AAPL)’s poaching of Kevin Lynch away from Adobe Systems Incorporation (NASDAQ:ADBE), where he helped hone the company’s subscription-based services.

In addition to the major new app Morgan Stanley (NYSE:MS) analysts are looking for, they’re also expecting a lighter 9.8-inch iPad and possible an iPad Mini in the September quarter. They also expect the iPhone 5S and a lower priced iPhone to launch in September.

Their expectations about the Apple Inc. (NASDAQ:AAPL) iPhone’s are similar to those made by Topeka Capital earlier this week, although Topeka is looking for two, if not three sizes of the new iPhone, and for them to come out in July rather than September.