Deprecation Guide for Ember.Component#defaultLayout

Specifying a defaultLayout to a component is deprecated in favor of specifying layout directly. defaultLayout was often used in order to allow inheriting components to fallback to their parents defaultLayout if a custom layout was not provided. Due to the way a components layout is looked up naturally, this is true when using layout properties in both locations. Changing the layout detection process allows initial render speed (with many components) to be improved pretty significantly.

Before:

// Ember < 2.1
import layout from '../templates/some-thing-lol';

export default Ember.Component.extend({
  defaultLayout: layout
});

After:

// Ember 2.1 and later
import layout from '../templates/some-thing-lol';

export default Ember.Component.extend({
  layout: layout
});