diff --git a/lib/classes/event/base.php b/lib/classes/event/base.php
index 6cbcbe223b5..d1cbe32c9a1 100644
--- a/lib/classes/event/base.php
+++ b/lib/classes/event/base.php
@@ -40,7 +40,7 @@ defined('MOODLE_INTERNAL') || die();
  * @property-read string $objecttable name of database table where is object record stored
  * @property-read int $objectid optional id of the object
  * @property-read string $crud letter indicating event type
- * @property-read int $level log level (number between 1 and 100)
+ * @property-read int $edulevel log level (one of the constants LEVEL_)
  * @property-read int $contextid
  * @property-read int $contextlevel
  * @property-read int $contextinstanceid
@@ -101,7 +101,7 @@ abstract class base implements \IteratorAggregate {
 
     /** @var array list of event properties */
     private static $fields = array(
-        'eventname', 'component', 'action', 'target', 'objecttable', 'objectid', 'crud', 'level', 'contextid',
+        'eventname', 'component', 'action', 'target', 'objecttable', 'objectid', 'crud', 'edulevel', 'contextid',
         'contextlevel', 'contextinstanceid', 'userid', 'courseid', 'relateduserid', 'other',
         'timecreated');
 
@@ -148,7 +148,7 @@ abstract class base implements \IteratorAggregate {
      * @throws \coding_exception
      */
     public static final function create(array $data = null) {
-        global $PAGE, $USER, $CFG;
+        global $USER, $CFG;
 
         $data = (array)$data;
 
@@ -161,6 +161,14 @@ abstract class base implements \IteratorAggregate {
         // Set static event data specific for child class.
         $event->init();
 
+        if (isset($event->data['level'])) {
+            if (!isset($event->data['edulevel'])) {
+                debugging('level property is deprecated, use edulevel property instead', DEBUG_DEVELOPER);
+                $event->data['edulevel'] = $event->data['level'];
+            }
+            unset($event->data['level']);
+        }
+
         // Set automatic data.
         $event->data['timecreated'] = time();
 
@@ -205,7 +213,7 @@ abstract class base implements \IteratorAggregate {
         // Warn developers if they do something wrong.
         if ($CFG->debugdeveloper) {
             static $automatickeys = array('eventname', 'component', 'action', 'target', 'contextlevel', 'contextinstanceid', 'timecreated');
-            static $initkeys = array('crud', 'level', 'objecttable');
+            static $initkeys = array('crud', 'level', 'objecttable', 'edulevel');
 
             foreach ($data as $key => $ignored) {
                 if ($key === 'context') {
@@ -234,7 +242,7 @@ abstract class base implements \IteratorAggregate {
      *
      * Set all required data properties:
      *  1/ crud - letter [crud]
-     *  2/ level - using a constant self::LEVEL_*.
+     *  2/ edulevel - using a constant self::LEVEL_*.
      *  3/ objecttable - name of database table if objectid specified
      *
      * Optionally it can set:
@@ -362,7 +370,7 @@ abstract class base implements \IteratorAggregate {
     /**
      * Return standardised event data as array.
      *
-     * @return array
+     * @return array All elements are scalars except the 'other' field which is array.
      */
     public function get_data() {
         return $this->data;
@@ -371,7 +379,9 @@ abstract class base implements \IteratorAggregate {
     /**
      * Return auxiliary data that was stored in logs.
      *
-     * TODO MDL-41331: Properly define this method once logging is finalised.
+     * List of standard properties:
+     *  - origin: IP number, cli,cron
+     *  - realuserid: id of the user when logged-in-as
      *
      * @return array the format is standardised by logging API
      */
@@ -425,8 +435,8 @@ abstract class base implements \IteratorAggregate {
         if (empty($this->data['crud'])) {
             throw new \coding_exception('crud must be specified in init() method of each method');
         }
-        if (!isset($this->data['level'])) {
-            throw new \coding_exception('level must be specified in init() method of each method');
+        if (!isset($this->data['edulevel'])) {
+            throw new \coding_exception('edulevel must be specified in init() method of each method');
         }
         if (!empty($this->data['objectid']) and empty($this->data['objecttable'])) {
             throw new \coding_exception('objecttable must be specified in init() method if objectid present');
@@ -439,9 +449,9 @@ abstract class base implements \IteratorAggregate {
             if (!in_array($this->data['crud'], array('c', 'r', 'u', 'd'), true)) {
                 debugging("Invalid event crud value specified.", DEBUG_DEVELOPER);
             }
-            if (!in_array($this->data['level'], array(self::LEVEL_OTHER, self::LEVEL_TEACHING, self::LEVEL_PARTICIPATING))) {
+            if (!in_array($this->data['edulevel'], array(self::LEVEL_OTHER, self::LEVEL_TEACHING, self::LEVEL_PARTICIPATING))) {
                 // Bitwise combination of levels is not allowed at this stage.
-                debugging('Event property level must a constant value, see event_base::LEVEL_*', DEBUG_DEVELOPER);
+                debugging('Event property edulevel must a constant value, see event_base::LEVEL_*', DEBUG_DEVELOPER);
             }
             if (self::$fields !== array_keys($this->data)) {
                 debugging('Number of event data fields must not be changed in event classes', DEBUG_DEVELOPER);
@@ -601,6 +611,10 @@ abstract class base implements \IteratorAggregate {
      * @return mixed
      */
     public function __get($name) {
+        if ($name === 'level') {
+            debugging('level property is deprecated, use edulevel property instead', DEBUG_DEVELOPER);
+            return $this->data['edulevel'];
+        }
         if (array_key_exists($name, $this->data)) {
             return $this->data[$name];
         }
@@ -630,6 +644,10 @@ abstract class base implements \IteratorAggregate {
      * @return bool
      */
     public function __isset($name) {
+        if ($name === 'level') {
+            debugging('level property is deprecated, use edulevel property instead', DEBUG_DEVELOPER);
+            return isset($this->data['edulevel']);
+        }
         return isset($this->data[$name]);
     }
 
diff --git a/lib/tests/event_test.php b/lib/tests/event_test.php
index 84b2bcdc2d4..a85276d5e89 100644
--- a/lib/tests/event_test.php
+++ b/lib/tests/event_test.php
@@ -52,7 +52,7 @@ class core_event_testcase extends advanced_testcase {
         $this->assertSame('unittest', $event->target);
         $this->assertSame(5, $event->objectid);
         $this->assertSame('u', $event->crud);
-        $this->assertSame(\core\event\base::LEVEL_PARTICIPATING, $event->level);
+        $this->assertSame(\core\event\base::LEVEL_PARTICIPATING, $event->edulevel);
 
         $this->assertEquals($system, $event->get_context());
         $this->assertSame($system->id, $event->contextid);
@@ -451,6 +451,23 @@ class core_event_testcase extends advanced_testcase {
             \core_tests\event\unittest_observer::$info);
     }
 
+    public function test_deprecated() {
+        global $DB;
+
+        $this->resetAfterTest(true);
+
+        $event = \core_tests\event\deprecated_event1::create();
+        $this->assertDebuggingCalled('level property is deprecated, use edulevel property instead');
+
+        $this->assertSame($event::LEVEL_TEACHING, $event->level);
+        $this->assertDebuggingCalled('level property is deprecated, use edulevel property instead');
+
+        $this->assertTrue(isset($event->level));
+        $this->assertDebuggingCalled('level property is deprecated, use edulevel property instead');
+
+        $this->assertSame($event::LEVEL_TEACHING, $event->edulevel);
+    }
+
     public function test_legacy() {
         global $DB;
 
diff --git a/lib/tests/fixtures/event_fixtures.php b/lib/tests/fixtures/event_fixtures.php
index 9cc8252d451..a516184ff04 100644
--- a/lib/tests/fixtures/event_fixtures.php
+++ b/lib/tests/fixtures/event_fixtures.php
@@ -41,7 +41,7 @@ class unittest_executed extends \core\event\base {
 
     protected function init() {
         $this->data['crud'] = 'u';
-        $this->data['level'] = self::LEVEL_PARTICIPATING;
+        $this->data['edulevel'] = self::LEVEL_PARTICIPATING;
     }
 
     public function get_url() {
@@ -116,14 +116,14 @@ class unittest_observer {
 class bad_event1 extends \core\event\base {
     protected function init() {
         //$this->data['crud'] = 'u';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
     }
 }
 
 class bad_event2 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'u';
-        //$this->data['level'] = 10;
+        //$this->data['edulevel'] = 10;
     }
 }
 
@@ -131,14 +131,14 @@ class bad_event2b extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'u';
         // Invalid level value.
-        $this->data['level'] = -1;
+        $this->data['edulevel'] = -1;
     }
 }
 
 class bad_event3 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'u';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         unset($this->data['courseid']);
     }
 }
@@ -146,7 +146,7 @@ class bad_event3 extends \core\event\base {
 class bad_event4 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'u';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->data['xxx'] = 1;
     }
 }
@@ -154,14 +154,14 @@ class bad_event4 extends \core\event\base {
 class bad_event5 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'x';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
     }
 }
 
 class bad_event6 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->data['objecttable'] = 'xxx_xxx_xx';
     }
 }
@@ -169,7 +169,7 @@ class bad_event6 extends \core\event\base {
 class bad_event7 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->data['objecttable'] = null;
     }
 }
@@ -177,7 +177,7 @@ class bad_event7 extends \core\event\base {
 class bad_event8 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->data['objecttable'] = 'user';
     }
 }
@@ -185,14 +185,14 @@ class bad_event8 extends \core\event\base {
 class problematic_event1 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'u';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
     }
 }
 
 class problematic_event2 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->context = \context_system::instance();
     }
 }
@@ -200,7 +200,7 @@ class problematic_event2 extends \core\event\base {
 class problematic_event3 extends \core\event\base {
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->context = \context_system::instance();
     }
 
@@ -211,11 +211,19 @@ class problematic_event3 extends \core\event\base {
     }
 }
 
+class deprecated_event1 extends \core\event\base {
+    protected function init() {
+        $this->data['crud'] = 'c';
+        $this->data['level'] = self::LEVEL_TEACHING; // Tests edulevel hint.
+        $this->context = \context_system::instance();
+    }
+}
+
 class noname_event extends \core\event\base {
 
     protected function init() {
         $this->data['crud'] = 'c';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->context = \context_system::instance();
     }
 }
@@ -237,7 +245,7 @@ class content_viewed extends \core\event\content_viewed {
 class course_module_viewed extends \core\event\course_module_viewed {
     protected function init() {
         $this->data['crud'] = 'r';
-        $this->data['level'] = self::LEVEL_OTHER;
+        $this->data['edulevel'] = self::LEVEL_OTHER;
         $this->data['objecttable'] = 'feedback';
     }
 }
diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 15a06cabafa..bd1a65200c6 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -6,6 +6,7 @@ information provided here is intended especially for developers.
 * $core_renderer->block_move_target() changed to support more verbose move-block-here descriptions.
 
 DEPRECATIONS:
+* Update init methods in all event classes - "level" property was renamed to "edulevel", the level property is now deprecated.
 * Abstract class \core\event\course_module_instances_list_viewed is deprecated now, use \core\event\instances_list_viewed instead.
 * mod_book\event\instances_list_viewed has been deprecated. Please use mod_book\event\course_module_instance_list_viewed instead.
 * mod_chat\event\instances_list_viewed has been deprecated. Please use mod_chat\event\course_module_instance_list_viewed instead.