Business Insider Intelligence Blix, which has filed a lawsuit against Apple in the past accusing it of infringing on its technology, says Apple delayed approving an update to its BlueMail app for weeks. According to emails reviewed by Business Insider, Apple rejected Blix's app update for not including Apple's "Sign in with Apple" feature, a requirement for apps that offer a sign in option from another service. Since Blix is an email app, it should have been exempt from that rule.