Apple has long inspired an almost religious devotion among customers and tech aficionados — but it just seriously undermined its fans' faith and loyalty. The company on Wednesday acknowledged what some people have long suspected: that it has been secretly stifling the performance of older iPhones. Critics have accused the company in the past, based on anecdotal evidence, of purposely slowing phones to compel users to upgrade to the latest model. While Apple admitted to the practice on Wednesday, it sought to underscore that it had done so for a purely altruistic reason: to prevent older phones from shutting down...