diff --git a/core/lib/Drupal/Core/Datetime/DateFormatInterface.php b/core/lib/Drupal/Core/Datetime/DateFormatInterface.php
index 810af6d..00c0073 100644
--- a/core/lib/Drupal/Core/Datetime/DateFormatInterface.php
+++ b/core/lib/Drupal/Core/Datetime/DateFormatInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a date format.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Datetime\Entity\DateFormat instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\Core\Datetime\Entity\DateFormat.
  */
 interface DateFormatInterface extends ConfigEntityInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php b/core/lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php
index a49d223..46b6d91 100644
--- a/core/lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php
+++ b/core/lib/Drupal/Core/Entity/Display/EntityDisplayInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides a common interface for entity displays.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\EntityDisplayBase instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\Core\Entity\EntityDisplayBase.
  */
 interface EntityDisplayInterface extends ConfigEntityInterface, EntityWithPluginCollectionInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/Display/EntityFormDisplayInterface.php b/core/lib/Drupal/Core/Entity/Display/EntityFormDisplayInterface.php
index 068c41f..2b4c5f3 100644
--- a/core/lib/Drupal/Core/Entity/Display/EntityFormDisplayInterface.php
+++ b/core/lib/Drupal/Core/Entity/Display/EntityFormDisplayInterface.php
@@ -13,6 +13,11 @@
 
 /**
  * Provides a common interface for entity form displays.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\Entity\EntityFormDisplay instead. In order
+ *   to replace an entity class using hook_entity_type_alter() the new class
+ *   must extend \Drupal\Core\Entity\Entity\EntityFormDisplay.
  */
 interface EntityFormDisplayInterface extends EntityDisplayInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/Display/EntityViewDisplayInterface.php b/core/lib/Drupal/Core/Entity/Display/EntityViewDisplayInterface.php
index ce54810..943f8e8 100644
--- a/core/lib/Drupal/Core/Entity/Display/EntityViewDisplayInterface.php
+++ b/core/lib/Drupal/Core/Entity/Display/EntityViewDisplayInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides a common interface for entity view displays.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\Entity\EntityViewDisplay instead. In order
+ *   to replace an entity class using hook_entity_type_alter() the new class
+ *   must extend \Drupal\Core\Entity\Entity\EntityViewDisplay.
  */
 interface EntityViewDisplayInterface extends EntityDisplayInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityDisplayModeInterface.php b/core/lib/Drupal/Core/Entity/EntityDisplayModeInterface.php
index 2575346..86c5ad8 100644
--- a/core/lib/Drupal/Core/Entity/EntityDisplayModeInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityDisplayModeInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface for entity types that hold form and view mode settings.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\EntityDisplayModeBase instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\Core\Entity\EntityDisplayModeBase.
  */
 interface EntityDisplayModeInterface extends ConfigEntityInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php b/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php
index 6fdecee..43efa09 100644
--- a/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityFormModeInterface.php
@@ -9,6 +9,11 @@
 
 /**
  * Provides an interface defining an entity form mode entity type.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\Entity\EntityFormMode instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\Core\Entity\Entity\EntityFormMode.
  */
 interface EntityFormModeInterface extends EntityDisplayModeInterface {
 
diff --git a/core/lib/Drupal/Core/Entity/EntityViewModeInterface.php b/core/lib/Drupal/Core/Entity/EntityViewModeInterface.php
index f2bfe7c..887780c 100644
--- a/core/lib/Drupal/Core/Entity/EntityViewModeInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityViewModeInterface.php
@@ -9,6 +9,11 @@
 
 /**
  * Provides an interface defining an entity view mode entity type.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Entity\Entity\EntityViewMode instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\Core\Entity\Entity\EntityViewMode.
  */
 interface EntityViewModeInterface extends EntityDisplayModeInterface {
 
diff --git a/core/lib/Drupal/Core/Field/FieldConfigInterface.php b/core/lib/Drupal/Core/Field/FieldConfigInterface.php
index ff8501f..2213709 100644
--- a/core/lib/Drupal/Core/Field/FieldConfigInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldConfigInterface.php
@@ -18,6 +18,11 @@
  *
  * @see \Drupal\Core\Field\Entity\BaseFieldOverride
  * @see \Drupal\field\Entity\FieldConfig
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\Core\Field\FieldConfigBase instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\Core\Field\FieldConfigBase.
  */
 interface FieldConfigInterface extends FieldDefinitionInterface, ConfigEntityInterface {
 
diff --git a/core/modules/aggregator/src/FeedInterface.php b/core/modules/aggregator/src/FeedInterface.php
index c5c7014..239cbc6 100644
--- a/core/modules/aggregator/src/FeedInterface.php
+++ b/core/modules/aggregator/src/FeedInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining an aggregator feed entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\aggregator\Entity\Feed instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\aggregator\Entity\Feed.
  */
 interface FeedInterface extends ContentEntityInterface {
 
diff --git a/core/modules/aggregator/src/ItemInterface.php b/core/modules/aggregator/src/ItemInterface.php
index 8211d35..e69b5e6 100644
--- a/core/modules/aggregator/src/ItemInterface.php
+++ b/core/modules/aggregator/src/ItemInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining an aggregator item entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\aggregator\Entity\Item instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\aggregator\Entity\Item.
  */
 interface ItemInterface extends ContentEntityInterface {
 
diff --git a/core/modules/block/src/BlockInterface.php b/core/modules/block/src/BlockInterface.php
index 8955be1..25143e3 100644
--- a/core/modules/block/src/BlockInterface.php
+++ b/core/modules/block/src/BlockInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a block entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\block\Entity\Block instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\block\Entity\Block.
  */
 interface BlockInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/block_content/src/BlockContentInterface.php b/core/modules/block_content/src/BlockContentInterface.php
index 50f4d35..c3c65ac 100644
--- a/core/modules/block_content/src/BlockContentInterface.php
+++ b/core/modules/block_content/src/BlockContentInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides an interface defining a custom block entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\block_content\Entity\BlockContent instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\block_content\Entity\BlockContent.
  */
 interface BlockContentInterface extends ContentEntityInterface, EntityChangedInterface {
 
diff --git a/core/modules/block_content/src/BlockContentTypeInterface.php b/core/modules/block_content/src/BlockContentTypeInterface.php
index 854f413..e78a272 100644
--- a/core/modules/block_content/src/BlockContentTypeInterface.php
+++ b/core/modules/block_content/src/BlockContentTypeInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a custom block type entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\block_content\Entity\BlockContentType instead. In order
+ *   to replace an entity class using hook_entity_type_alter() the new class
+ *   must extend \Drupal\block_content\Entity\BlockContentType.
  */
 interface BlockContentTypeInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/comment/src/CommentInterface.php b/core/modules/comment/src/CommentInterface.php
index 0d558b5..67ee107 100644
--- a/core/modules/comment/src/CommentInterface.php
+++ b/core/modules/comment/src/CommentInterface.php
@@ -13,6 +13,11 @@
 
 /**
  * Provides an interface defining a comment entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\comment\Entity\Comment instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\comment\Entity\Comment.
  */
 interface CommentInterface extends ContentEntityInterface, EntityChangedInterface, EntityOwnerInterface {
 
diff --git a/core/modules/comment/src/CommentTypeInterface.php b/core/modules/comment/src/CommentTypeInterface.php
index a1f826e..316fcad 100644
--- a/core/modules/comment/src/CommentTypeInterface.php
+++ b/core/modules/comment/src/CommentTypeInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a comment type entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\comment\Entity\CommentType instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\comment\Entity\CommentType.
  */
 interface CommentTypeInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/config/tests/config_test/src/ConfigTestInterface.php b/core/modules/config/tests/config_test/src/ConfigTestInterface.php
index 76cb2e3..e0c0b2f 100644
--- a/core/modules/config/tests/config_test/src/ConfigTestInterface.php
+++ b/core/modules/config/tests/config_test/src/ConfigTestInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a config_test entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\config_test\Entity\ConfigTest instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\config_test\Entity\ConfigTest.
  */
 interface ConfigTestInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/contact/src/ContactFormInterface.php b/core/modules/contact/src/ContactFormInterface.php
index 8f588ee..8e10739 100644
--- a/core/modules/contact/src/ContactFormInterface.php
+++ b/core/modules/contact/src/ContactFormInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a contact form entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\contact\Entity\ContactForm instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\contact\Entity\ContactForm.
  */
 interface ContactFormInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/contact/src/MessageInterface.php b/core/modules/contact/src/MessageInterface.php
index 98f5e9a..7d707ba 100644
--- a/core/modules/contact/src/MessageInterface.php
+++ b/core/modules/contact/src/MessageInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a contact message entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\contact\Entity\Message instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\contact\Entity\Message.
  */
 interface MessageInterface extends ContentEntityInterface {
 
diff --git a/core/modules/editor/src/EditorInterface.php b/core/modules/editor/src/EditorInterface.php
index 64466ba..8e7b927 100644
--- a/core/modules/editor/src/EditorInterface.php
+++ b/core/modules/editor/src/EditorInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a text editor entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\editor\Entity\Editor instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\editor\Entity\Editor.
  */
 interface EditorInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/field/src/FieldConfigInterface.php b/core/modules/field/src/FieldConfigInterface.php
index 5a8dfdb..bce016e 100644
--- a/core/modules/field/src/FieldConfigInterface.php
+++ b/core/modules/field/src/FieldConfigInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides an interface defining a field entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\field\Entity\FieldConfig instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\field\Entity\FieldConfig.
  */
 interface FieldConfigInterface extends ConfigEntityInterface, FieldDefinitionInterface {
 
diff --git a/core/modules/field/src/FieldStorageConfigInterface.php b/core/modules/field/src/FieldStorageConfigInterface.php
index 3f44818..648aae4 100644
--- a/core/modules/field/src/FieldStorageConfigInterface.php
+++ b/core/modules/field/src/FieldStorageConfigInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides an interface defining a field storage entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\field\Entity\FieldStorageConfig instead. In order to
+ *   replace an entity class using hook_entity_type_alter() the new class must
+ *   extend \Drupal\field\Entity\FieldStorageConfig.
  */
 interface FieldStorageConfigInterface extends ConfigEntityInterface, FieldStorageDefinitionInterface {
 
diff --git a/core/modules/file/src/FileInterface.php b/core/modules/file/src/FileInterface.php
index 1b02d1f..5bc976d 100644
--- a/core/modules/file/src/FileInterface.php
+++ b/core/modules/file/src/FileInterface.php
@@ -13,6 +13,11 @@
 
 /**
  * Defines getter and setter methods for file entity base fields.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\file\Entity\File instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\file\Entity\File.
  */
 interface FileInterface extends ContentEntityInterface, EntityChangedInterface, EntityOwnerInterface {
 
diff --git a/core/modules/filter/src/FilterFormatInterface.php b/core/modules/filter/src/FilterFormatInterface.php
index b9c558b..c1a1b24 100644
--- a/core/modules/filter/src/FilterFormatInterface.php
+++ b/core/modules/filter/src/FilterFormatInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a filter format entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\filter\Entity\FilterFormat instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\filter\Entity\FilterFormat.
  */
 interface FilterFormatInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/image/src/ImageStyleInterface.php b/core/modules/image/src/ImageStyleInterface.php
index 39bb583..5013eb6 100644
--- a/core/modules/image/src/ImageStyleInterface.php
+++ b/core/modules/image/src/ImageStyleInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining an image style entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\image\Entity\ImageStyle instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\image\Entity\ImageStyle.
  */
 interface ImageStyleInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/language/src/ConfigurableLanguageInterface.php b/core/modules/language/src/ConfigurableLanguageInterface.php
index 9106df5..074e3f7 100644
--- a/core/modules/language/src/ConfigurableLanguageInterface.php
+++ b/core/modules/language/src/ConfigurableLanguageInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides an interface defining a language entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\language\Entity\ConfigurableLanguage instead. In order
+ *   to replace an entity class using hook_entity_type_alter() the new class
+ *   must extend \Drupal\language\Entity\ConfigurableLanguage.
  */
 interface ConfigurableLanguageInterface extends ConfigEntityInterface, LanguageInterface {
 
diff --git a/core/modules/language/src/ContentLanguageSettingsInterface.php b/core/modules/language/src/ContentLanguageSettingsInterface.php
index 9ee0893..5353dcd 100644
--- a/core/modules/language/src/ContentLanguageSettingsInterface.php
+++ b/core/modules/language/src/ContentLanguageSettingsInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining language settings for content entities.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\language\Entity\ContentLanguageSettings instead. In
+ *   order to replace an entity class using hook_entity_type_alter() the new
+ *   class must extend \Drupal\language\Entity\ContentLanguageSettings.
  */
 interface ContentLanguageSettingsInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/menu_link_content/src/MenuLinkContentInterface.php b/core/modules/menu_link_content/src/MenuLinkContentInterface.php
index d2b8254..a59a020 100644
--- a/core/modules/menu_link_content/src/MenuLinkContentInterface.php
+++ b/core/modules/menu_link_content/src/MenuLinkContentInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Defines an interface for custom menu links.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\menu_link_content\Entity\MenuLinkContent instead. In
+ *   order to replace an entity class using hook_entity_type_alter() the new
+ *   class must extend \Drupal\menu_link_content\Entity\MenuLinkContent.
  */
 interface MenuLinkContentInterface extends ContentEntityInterface, EntityChangedInterface {
 
diff --git a/core/modules/migrate/src/Entity/MigrationInterface.php b/core/modules/migrate/src/Entity/MigrationInterface.php
index a07c0ea..d18e4f1 100644
--- a/core/modules/migrate/src/Entity/MigrationInterface.php
+++ b/core/modules/migrate/src/Entity/MigrationInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Interface for migrations.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\migrate\Entity\Migration instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\migrate\Entity\Migration.
  */
 interface MigrationInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/node/src/NodeInterface.php b/core/modules/node/src/NodeInterface.php
index 241fb1a..55d039e 100644
--- a/core/modules/node/src/NodeInterface.php
+++ b/core/modules/node/src/NodeInterface.php
@@ -13,6 +13,11 @@
 
 /**
  * Provides an interface defining a node entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\node\Entity\Node instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\node\Entity\Node.
  */
 interface NodeInterface extends ContentEntityInterface, EntityChangedInterface, EntityOwnerInterface {
 
diff --git a/core/modules/node/src/NodeTypeInterface.php b/core/modules/node/src/NodeTypeInterface.php
index 5ba0f94..bd2d1c3 100644
--- a/core/modules/node/src/NodeTypeInterface.php
+++ b/core/modules/node/src/NodeTypeInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a node type entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\node\Entity\NodeType instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\node\Entity\NodeType.
  */
 interface NodeTypeInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/rdf/src/RdfMappingInterface.php b/core/modules/rdf/src/RdfMappingInterface.php
index 1f78b47..8ece103 100644
--- a/core/modules/rdf/src/RdfMappingInterface.php
+++ b/core/modules/rdf/src/RdfMappingInterface.php
@@ -10,6 +10,11 @@
 
 /**
  * Provides an interface defining an RDF mapping entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\rdf\Entity\RdfMapping instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\rdf\Entity\RdfMapping.
  */
 interface RdfMappingInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/responsive_image/src/ResponsiveImageStyleInterface.php b/core/modules/responsive_image/src/ResponsiveImageStyleInterface.php
index 3c8d7ba..924bc1c 100644
--- a/core/modules/responsive_image/src/ResponsiveImageStyleInterface.php
+++ b/core/modules/responsive_image/src/ResponsiveImageStyleInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a responsive_image mapping entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\responsive_image\Entity\ResponsiveImageStyle instead. In
+ *   order to replace an entity class using hook_entity_type_alter() the new
+ *   class must extend \Drupal\responsive_image\Entity\ResponsiveImageStyle.
  */
 interface ResponsiveImageStyleInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/search/src/SearchPageInterface.php b/core/modules/search/src/SearchPageInterface.php
index dae91f9..b91247b 100644
--- a/core/modules/search/src/SearchPageInterface.php
+++ b/core/modules/search/src/SearchPageInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a search page entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\search\Entity\SearchPage instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\search\Entity\SearchPage.
  */
 interface SearchPageInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/shortcut/src/ShortcutInterface.php b/core/modules/shortcut/src/ShortcutInterface.php
index 5c33a7f..a427837 100644
--- a/core/modules/shortcut/src/ShortcutInterface.php
+++ b/core/modules/shortcut/src/ShortcutInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a shortcut entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\shortcut\Entity\Shortcut instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\shortcut\Entity\Shortcut.
  */
 interface ShortcutInterface extends ContentEntityInterface {
 
diff --git a/core/modules/shortcut/src/ShortcutSetInterface.php b/core/modules/shortcut/src/ShortcutSetInterface.php
index 9d2f941..499ed5b 100644
--- a/core/modules/shortcut/src/ShortcutSetInterface.php
+++ b/core/modules/shortcut/src/ShortcutSetInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a shortcut set entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\shortcut\Entity\ShortcutSet instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\shortcut\Entity\ShortcutSet.
  */
 interface ShortcutSetInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/system/src/ActionConfigEntityInterface.php b/core/modules/system/src/ActionConfigEntityInterface.php
index 32b41b0..b65f53e 100644
--- a/core/modules/system/src/ActionConfigEntityInterface.php
+++ b/core/modules/system/src/ActionConfigEntityInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a action entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\system\Entity\Action instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\system\Entity\Action.
  */
 interface ActionConfigEntityInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/system/src/MenuInterface.php b/core/modules/system/src/MenuInterface.php
index baa8173..973bf0d 100644
--- a/core/modules/system/src/MenuInterface.php
+++ b/core/modules/system/src/MenuInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a menu entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\system\Entity\Menu instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\system\Entity\Menu.
  */
 interface MenuInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/taxonomy/src/TermInterface.php b/core/modules/taxonomy/src/TermInterface.php
index 89ff3fc..4fbe962 100644
--- a/core/modules/taxonomy/src/TermInterface.php
+++ b/core/modules/taxonomy/src/TermInterface.php
@@ -12,6 +12,11 @@
 
 /**
  * Provides an interface defining a taxonomy term entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\taxonomy\Entity\Term instead. In order to replace an
+ *   entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\taxonomy\Entity\Term.
  */
 interface TermInterface extends ContentEntityInterface, EntityChangedInterface {
 
diff --git a/core/modules/taxonomy/src/VocabularyInterface.php b/core/modules/taxonomy/src/VocabularyInterface.php
index e6e9e79..e8d85e4 100644
--- a/core/modules/taxonomy/src/VocabularyInterface.php
+++ b/core/modules/taxonomy/src/VocabularyInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a taxonomy vocabulary entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\taxonomy\Entity\Vocabulary instead. In order to replace
+ *   an entity class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\taxonomy\Entity\Vocabulary.
  */
 interface VocabularyInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/tour/src/TourInterface.php b/core/modules/tour/src/TourInterface.php
index afccc5d..e1a72c8 100644
--- a/core/modules/tour/src/TourInterface.php
+++ b/core/modules/tour/src/TourInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Provides an interface defining a tour entity.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\tour\Entity\Tour instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\tour\Entity\Tour.
  */
 interface TourInterface extends ConfigEntityInterface {
 
diff --git a/core/modules/user/src/RoleInterface.php b/core/modules/user/src/RoleInterface.php
index 0d692b8..f6ea50f 100644
--- a/core/modules/user/src/RoleInterface.php
+++ b/core/modules/user/src/RoleInterface.php
@@ -13,6 +13,11 @@
 /**
  * Provides an interface defining a user role entity.
  *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\user\Entity\Role instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\user\Entity\Role.
+ *
  * @ingroup user_api
  */
 interface RoleInterface extends ConfigEntityInterface {
diff --git a/core/modules/user/src/UserInterface.php b/core/modules/user/src/UserInterface.php
index 17f7b16..452ecda 100644
--- a/core/modules/user/src/UserInterface.php
+++ b/core/modules/user/src/UserInterface.php
@@ -14,6 +14,11 @@
 /**
  * Provides an interface defining a user entity.
  *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\user\Entity\User instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\user\Entity\User.
+ *
  * @ingroup user_api
  */
 interface UserInterface extends ContentEntityInterface, EntityChangedInterface, AccountInterface {
diff --git a/core/modules/views/src/ViewEntityInterface.php b/core/modules/views/src/ViewEntityInterface.php
index 68dbc14..196373d 100644
--- a/core/modules/views/src/ViewEntityInterface.php
+++ b/core/modules/views/src/ViewEntityInterface.php
@@ -11,6 +11,11 @@
 
 /**
  * Defines an interface for View storage classes.
+ *
+ * @deprecated in Drupal 8.1.x and will be removed before 9.0.0. Typehints
+ *   should use \Drupal\views\Entity\View instead. In order to replace an entity
+ *   class using hook_entity_type_alter() the new class must extend
+ *   \Drupal\views\Entity\View.
  */
 interface ViewEntityInterface extends ConfigEntityInterface {