Flutter 3.47 makes the standalone Material and Cupertino 1.0 packages opt-in, with in-SDK deprecation scheduled for November

Sources: primary, discussion
Summary: Flutter 3.47 publishes standalone material_ui and cupertino_ui 1.0 packages that an application opts in to, and the core SDK still includes the in-SDK libraries in this release. The post schedules formal deprecation of the in-SDK libraries for the November stable release, and ships an automated migration through dart fix --apply --code=migrate_design_widgets plus a MaterialUiCompatibilityBridge for partially migrated dependency trees. The release also raises the minimum to iOS 15 and macOS 12, makes Impeller the default renderer on macOS, Windows, and Linux, and warns that an app built with Xcode 27 that has custom AppDelegate code and does not adopt the UIScene lifecycle will fail to launch.
Why it matters: The widget library split is opt-in and has tooling behind it, so the dated obligations in this release are the raised platform minimums and the UIScene lifecycle requirement, with in-SDK deprecation following in November.
Follow-up: Confirm the November stable release when it lands and record whether the in-SDK deprecation holds to that date.