Change record status: 
Project: 
Introduced in branch: 
8.0.x
Description: 

A langcode entity key has been added to restore the functionality provided by the language entity key available in D7. The key value should match the entity language field name, all core entity types use 'langcode'.

D7:

function node_entity_info() {
  $return = array(
    'node' => array(
      'entity keys' => array(
        'id' => 'nid',
        'revision' => 'vid',
        'bundle' => 'type',
        'label' => 'title',
        'language' => 'language',
      ),
      // ...
    ),
  );

D8:

/**
 * Defines the node entity class.
 *
 * @ContentEntityType(
 *   id = "node",
 *   entity_keys = {
 *     "id" = "nid",
 *     "revision" = "vid",
 *     "bundle" = "type",
 *     "label" = "title",
 *     "langcode" = "langcode",
 *     "uuid" = "uuid"
 *   },
 *   ...
 * )
 */
class Node extends ContentEntityBase implements NodeInterface {
  // ...
}
Impacts: 
Module developers
Updates Done (doc team, etc.)
Online documentation: 
Not done
Theming guide: 
Not done
Module developer documentation: 
Not done
Examples project: 
Not done
Coder Review: 
Not done
Coder Upgrade: 
Not done
Other: 
Other updates done