diff --git a/lang/en/deprecated.txt b/lang/en/deprecated.txt
index 5a3e19451a1..873ad79c53c 100644
--- a/lang/en/deprecated.txt
+++ b/lang/en/deprecated.txt
@@ -135,3 +135,5 @@ keepsearching,core
 allfieldsrequired,core
 previewhtml,core
 messagedselecteduserfailed,core
+eventmessagecontactblocked,core_message
+eventmessagecontactunblocked,core_message
diff --git a/lang/en/message.php b/lang/en/message.php
index 4517a303a1a..ad1fd6c33c4 100644
--- a/lang/en/message.php
+++ b/lang/en/message.php
@@ -48,9 +48,7 @@ $string['errortranslatingdefault'] = 'Error translating default setting provided
 $string['eventnotificationviewed'] = 'Notification viewed';
 $string['eventnotificationsent'] = 'Notification sent';
 $string['eventmessagecontactadded'] = 'Message contact added';
-$string['eventmessagecontactblocked'] = 'Message contact blocked';
 $string['eventmessagecontactremoved'] = 'Message contact removed';
-$string['eventmessagecontactunblocked'] = 'Message contact unblocked';
 $string['eventmessagedeleted'] = 'Message deleted';
 $string['eventmessageviewed'] = 'Message viewed';
 $string['eventmessagesent'] = 'Message sent';
@@ -180,4 +178,6 @@ $string['writeamessage'] = 'Write a message...';
 $string['you'] = 'You:';
 
 // Deprecated since Moodle 3.6.
+$string['eventmessagecontactblocked'] = 'Message contact blocked';
+$string['eventmessagecontactunblocked'] = 'Message contact unblocked';
 $string['messagingdisabled'] = 'Messaging is disabled on this site, emails will be sent instead';
diff --git a/lib/classes/event/message_contact_blocked.php b/lib/classes/event/message_contact_blocked.php
index da9fc4cfa61..1c207a3e8dc 100644
--- a/lib/classes/event/message_contact_blocked.php
+++ b/lib/classes/event/message_contact_blocked.php
@@ -26,6 +26,9 @@ namespace core\event;
 
 defined('MOODLE_INTERNAL') || die();
 
+debugging('core\\event\\message_contact_blocked has been deprecated. Please use
+        core\\event\\message_user_blocked instead', DEBUG_DEVELOPER);
+
 /**
  * Message contact blocked event class.
  *
@@ -99,4 +102,13 @@ class message_contact_blocked extends base {
         // Messaging contacts are not backed up, so no need to map them on restore.
         return array('db' => 'message_contacts', 'restore' => base::NOT_MAPPED);
     }
+
+    /**
+     * This event has been deprecated.
+     *
+     * @return boolean
+     */
+    public static function is_deprecated() {
+        return true;
+    }
 }
diff --git a/lib/classes/event/message_contact_unblocked.php b/lib/classes/event/message_contact_unblocked.php
index 417a1a6c3cc..61f83e6ab14 100644
--- a/lib/classes/event/message_contact_unblocked.php
+++ b/lib/classes/event/message_contact_unblocked.php
@@ -26,6 +26,9 @@ namespace core\event;
 
 defined('MOODLE_INTERNAL') || die();
 
+debugging('core\\event\\message_contact_unblocked has been deperecated. Please use
+        core\\event\\message_user_unblocked instead', DEBUG_DEVELOPER);
+
 /**
  * Message contact unblocked event class.
  *
@@ -99,4 +102,13 @@ class message_contact_unblocked extends base {
         // Messaging contacts are not backed up, so no need to map them on restore.
         return array('db' => 'message_contacts', 'restore' => base::NOT_MAPPED);
     }
+
+    /**
+     * This event has been deprecated.
+     *
+     * @return boolean
+     */
+    public static function is_deprecated() {
+        return true;
+    }
 }