This is a prerequisite. To enable migration, we must support all migration states (legacy KGP and Built-in Kotlin) across apps and plugins, we have to:

• [AGP 9] Raise KGP Error and Warn Version #184384
• [AGP 9] Add Support for Built-in Kotlin in FGP #183909
• [AGP 9] Disable Built-in Kotlin By Default #183910

Ecosystem Migration

• [AGP 9] Migrate Flutter Plugin Modules to Support AGP 9 #187261
• [AGP 9] Migrate All Plugin Example Apps to Built-in Kotlin #187325
• [AGP 9] Enable Built-in Kotlin for the modern build-all in packages #187523
• [AGP 9] Add Support To Enable Built-in Kotlin #187712
• [AGP 9] Ensure Warnings Do Not Log When AGP Is Below 9 #188373
• Track top plugin migration, file issues
• start warning plugin authors of affected pub scores
• Start docking pub scores

Remove support for the legacy KGP state. By this time apps and plugins should be migrated:

• [AGP 9] Remove Support for KGP #184837