Apple Inc. has set an internal release target of spring 2026 for its delayed upgrade of Siri, marking a key step in its artificial intelligence turnaround effort. The company’s Siri team is aiming to bring the revamped voice assistant to market as part of an iOS 26.4 software update, according to people with knowledge of the matter. The long-promised changes will allow Siri to tap into consumers’ personal data and on-screen activities in order to better fulfill queries....