https://wccftech.com/apple-is-changing-ios-14-development-process-after-buggy-ios-13-release/

Apple is reportedly overhauling its software development and testing processes for iOS 14, codenamed "Azul", after the buggy release of iOS 13 and iPadOS 13. The revamped software testing process will also have an impact on 2020's iPadOS, watchOS, macOS and tvOS updates. The company will prioritize testing by modularizing various operating system features, and allowing testers to enable and disable them individually to measure their impact on operating system stability.

Craig Federighi, Senior Vice President of Software Engineering at Apple, rallied his troops at an internal kickoff meeting and introduced a new process to ensure that future software updates are as bug-free as possible. Daily internal builds for operating system updates will have the capability (called Flags) for new and work-in-progress features to be disabled by testers, so they can isolate bugs and performance impacts.