BlackBerry, the mobile platform most bankers had all but given up on, is showing signs of life.

The new Classic smartphone, which brings back some of the features "CrackBerry" addicts say they can't live without, sold out before its official launch Dec. 17. Last month, BlackBerry Ltd., formerly known as Research in Motion, bought a German outfit called Secusmart whose anti-theft and anti-eavesdropping technology should strengthen the security of BlackBerry's enterprise mobility software.

BlackBerry also inked a deal with AT&T to sell the Passport smartphone to U.S. customers, after agreeing to round off the device's square design. And it won a vote of confidence from PayPal, which launched a new payment app for the BlackBerry this month.

But so far, the changes seem unlikely to change the minds of banks, many of which have quietly discontinued or abandoned their native BlackBerry apps, in some cases downgrading them to links to a mobile web app.

Less than 2% of U.S. adults say BlackBerry is their primary smartphone, according to Mary Monahan, research director at Javelin Strategy & Research. This makes it hard for banks to justify investment in the platform.

"Banks are not putting resources into such a small market," she said. "The Classic will need to actually resuscitate BlackBerry's dismal performance over the past few years."

U.S. Bancorp, for instance, discontinued its native BlackBerry app in February 2013 and turned it into a bookmark for its mobile web app. The Minneapolis bank said its main criterion for creating a native app for a phone operating system is market share.

"We go by usage percentages," said Niti Badarinath, U.S. Bank's senior vice president for mobile banking and payments. "When we make an investment, we have to decide which apps to upgrade based on how many customers use the device."

BlackBerry users declined to less than 5% of U.S. Bank's customers in 2012. "We track the percentages of all the four big operating systems and we're still not seeing the kind of growth we need to in BlackBerry," Badarinath said.

If the ratio were to climb back above 5%, the bank would reconsider, but Badarinath said he doesn't expect this to happen in the coming year. The same is true for Microsoft Windows Mobile phones.

Further, building a native app makes sense when there are features that can be delivered over an app that a browser cannot support, Badarinath said. "If there's nothing different you can do in an app, why not use responsive design?"

The high-security BlackBerry operating system also blocks apps from controlling certain functions of the phone, he noted, which can affect a bank's ability to offer voice recognition and location awareness, for instance.

Nevertheless, Badarinath said he follows BlackBerry closely and approves of its recent moves.

"BlackBerry seems to have gone back to their roots. They decided they have strengths like encryption and delivery to the corporate space," he said. "I hear they're selling better than they used to."

BlackBerry did not answer questions about mobile banking apps. Nor would the company say how many BlackBerry Classic phones it had made available for sale.

Two selling points for the Classic are its old-fashioned physical QWERTY keyboard that longtime BlackBerry users prefer, and the fact that it can run some Android apps, though they have to be downloaded from the Amazon store.

Other banks, while technically updating their app up to the latest BlackBerry 10 operating system, appear to neglect it, as dozens of mostly terrible reviews linger unaddressed in the BlackBerry World app store.

Bank of America, for example, launched a new mobile banking app for BlackBerry 10 devices in May, and at the same time retired its BlackBerry 7 mobile app. Customers using older BlackBerry operating systems were notified in advance of the shutdown. But reviews of the new app in the BlackBerry World store are mostly negative, ranging from, "Useless - No deposits available via camera. Why bother. Just use the website," to "Poor app still does not load independent of using browser." Bank of America did not respond to a request for comment by deadline.

Even if the BlackBerry Classic fizzles, there is still a danger to letting a dated app that gets overwhelmingly bad reviews on the BlackBerry store languish.

"There's a real risk of having unsupported apps lying around, because mobile is evolving extremely quickly," said Jacob Jegher, research director at Celent. "Not supporting an app is the equivalent of letting it die. That's not a great strategy to put in front of a consumer."

The new PayPal app for BlackBerry lets users do most things the PayPal Android app does, like send and request money, check balances, see recent activity, redeem offers, make purchases and manage credit and debit cards from the app. PayPal decided to launch a BlackBerry app because "we want to be wherever our customers are," a company spokesman said.

Some financial institutions continue to devote resources to BlackBerry apps.

"We are still paying attention to our BlackBerry app and update it on a regular basis," said Charaka Kithulegoda, the chief information officer at Tangerine Bank in Canada.

"A significant portion of our client base uses the BlackBerry platform and we still consider BlackBerry part of our distribution strategy," said Kithulegoda, who tested the prerelease version of the Classic. "There is still a market for this still-important platform."