Some security experts who inspected that new version of iOS got a big surprise. They found that Apple had not obscured the workings of the heart of its operating system using encryption as the company has done before. Crucial pieces of the code destined to power millions of iPhones and iPads were laid bare for all to see. That would aid anyone looking for security weaknesses in Apple’s flagship software. Security experts say the famously secretive company may have adopted a bold new strategy intended to encourage more people to report bugs in its software—or perhaps made an embarrassing mistake....