Disable Access to Non-global Apex Controller Methods in Managed Packages (Critical Update)

This release includes a critical update that affects access to server-side Apex controller methods from your Lightning components. If you’ve written Lightning component code that calls non-global Apex methods in a managed package, you have some work to do.
As a reminder, the Apex methods behind your Lightning components server actions have the following access modifier requirements.
  • Apex methods in the same namespace as your component must be marked public or global.
  • Apex methods in a different namespace from your component must be marked global.

See the details, including changes you might need to make to your code, in the Apex release note Disable Access to Non-global Apex Controller Methods in Managed Packages (Critical Update).