diff --git a/src/LaunchDarkly/Impl/EventFactory.php b/src/LaunchDarkly/Impl/EventFactory.php
index 068ca4e5..4a3651f7 100644
--- a/src/LaunchDarkly/Impl/EventFactory.php
+++ b/src/LaunchDarkly/Impl/EventFactory.php
@@ -39,6 +39,9 @@ public function newEvalEvent($flag, $user, $detail, $default, $prereqOfFlag = nu
         if (($addExperimentData || $this->_withReasons) && $detail->getReason()) {
             $e['reason'] = $detail->getReason()->jsonSerialize();
         }
+        if ($user->getAnonymous()) {
+            $e['contextKind'] = 'anonymousUser';
+        }
         return $e;
     }
 
@@ -63,6 +66,9 @@ public function newDefaultEvent($flag, $user, $detail)
         if ($this->_withReasons && $detail->getReason()) {
             $e['reason'] = $detail->getReason()->jsonSerialize();
         }
+        if ($user->getAnonymous()) {
+            $e['contextKind'] = 'anonymousUser';
+        }
         return $e;
     }
 
@@ -80,6 +86,9 @@ public function newUnknownFlagEvent($key, $user, $detail)
         if ($this->_withReasons && $detail->getReason()) {
             $e['reason'] = $detail->getReason()->jsonSerialize();
         }
+        if ($user->getAnonymous()) {
+            $e['contextKind'] = 'anonymousUser';
+        }
         return $e;
     }
 
@@ -107,9 +116,35 @@ public function newCustomEvent($eventName, $user, $data, $metricValue)
         if (isset($metricValue)) {
             $e['metricValue'] = $metricValue;
         }
+        if ($user->getAnonymous()) {
+            $e['contextKind'] = 'anonymousUser';
+        }
+        return $e;
+    }
+
+    public function newAliasEvent($user, $previousUser)
+    {
+        $e = array(
+            'kind' => 'alias',
+            'key' => strval($user->getKey()),
+            'contextKind' => static::contextKind($user),
+            'previousKey' => strval($previousUser->getKey()),
+            'previousContextKind' => static::contextKind($previousUser),
+            'creationDate' => Util::currentTimeUnixMillis()
+        );
+
         return $e;
     }
 
+    private static function contextKind($user)
+    {
+        if ($user->getAnonymous()) {
+            return 'anonymousUser';
+        } else {
+            return 'user';
+        }
+    }
+
     private static function isExperiment($flag, $reason)
     {
         if ($reason) {
diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
index 5e338d31..f0a6cace 100644
--- a/src/LaunchDarkly/LDClient.php
+++ b/src/LaunchDarkly/LDClient.php
@@ -375,7 +375,7 @@ public function allFlags($user)
     public function allFlagsState($user, $options = array())
     {
         if (is_null($user) || is_null($user->getKey())) {
-            $this->_logger->warn("allFlagsState called with null user or null/empty user key! Returning empty state");
+            $this->_logger->warning("allFlagsState called with null user or null/empty user key! Returning empty state");
             return new FeatureFlagsState(false);
         }
         if ($this->isOffline()) {
@@ -408,6 +408,34 @@ public function allFlagsState($user, $options = array())
         return $state;
     }
 
+    /**
+     * Associates two users for analytics purposes.
+     *
+     * This can be helpful in the situation where a person is represented by multiple
+     * LaunchDarkly users. This may happen, for example, when a person initially logs into
+     * an application-- the person might be represented by an anonymous user prior to logging
+     * in and a different user after logging in, as denoted by a different user key.
+     *
+     * @param LDUser $user the newly identified user.
+     * @param LDUser $previousUser the previously identified user.
+     * @return void
+     */
+    public function alias($user, $previousUser)
+    {
+        if (is_null($user) || is_null($user->getKey())) {
+            $this->_logger->warning("Alias called with null user or null/empty user!");
+            return;
+        }
+
+        if (is_null($previousUser) || is_null($previousUser->getKey())) {
+            $this->_logger->warning("Alias called with null user or null/empty previousUser!");
+            return;
+        }
+
+        $event = $this->_eventFactoryDefault->newAliasEvent($user, $previousUser);
+        $this->_eventProcessor->enqueue($event);
+    }
+
     /**
      * Generates an HMAC sha256 hash for use in Secure mode.
      *
diff --git a/tests/LDClientTest.php b/tests/LDClientTest.php
index 8d522eff..e21e9ded 100644
--- a/tests/LDClientTest.php
+++ b/tests/LDClientTest.php
@@ -313,6 +313,27 @@ public function testVariationDetailSendsEventForUnknownFlag()
         $this->assertEquals(array('kind' => 'ERROR', 'errorKind' => 'FLAG_NOT_FOUND'), $event['reason']);
     }
 
+
+    public function testVariationWithAnonymousUserSendsEventWithAnonymousContextKind()
+    {
+        $ep = new MockEventProcessor();
+        $client = $this->makeClient(array('event_processor' => $ep));
+
+        $flag = $this->makeOffFlagWithValue('feature', 'value');
+
+        $anon_builder = new LDUserBuilder("anon@email.com");
+        $anon = $anon_builder->anonymous(true)->build();
+
+        $client->variation('feature', $anon, 'default');
+
+        $queue = $ep->getEvents();
+        $this->assertEquals(1, sizeof($queue));
+
+        $event = $queue[0];
+
+        $this->assertEquals('anonymousUser', $event['contextKind']);
+    }
+
     public function testAllFlagsReturnsFlagValues()
     {
         $flagJson = array(
@@ -593,6 +614,46 @@ public function testTrackSendsEventWithDataAndMetricValue()
         $this->assertEquals($metricValue, $event['metricValue']);
     }
 
+    public function testTrackWithAnonymousUserSendsEventWithAnonymousContextKind()
+    {
+        $ep = new MockEventProcessor();
+        $client = $this->makeClient(array('event_processor' => $ep));
+
+        $anon_builder = new LDUserBuilder("anon@email.com");
+        $anon = $anon_builder->anonymous(true)->build();
+
+        $client->track('eventkey', $anon);
+        $queue = $ep->getEvents();
+        $this->assertEquals(1, sizeof($queue));
+        $event = $queue[0];
+        $this->assertEquals('custom', $event['kind']);
+        $this->assertEquals('anonymousUser', $event['contextKind']);
+    }
+
+    public function testAliasEventsAreCorrect()
+    {
+        $ep = new MockEventProcessor();
+        $client = $this->makeClient(array('event_processor' => $ep));
+        
+        $user_builder = new LDUserBuilder("user@email.com");
+        $user = $user_builder->anonymous(false)->build();
+        $anon_builder = new LDUserBuilder("anon@email.com");
+        $anon = $anon_builder->anonymous(true)->build();
+
+        $client->alias($user, $anon);
+
+        $queue = $ep->getEvents();
+        $this->assertEquals(1, sizeof($queue));
+
+        $event = $queue[0];
+
+        $this->assertEquals('alias', $event['kind']);
+        $this->assertEquals($user->getKey(), $event['key']);
+        $this->assertEquals('user', $event['contextKind']);
+        $this->assertEquals($anon->getKey(), $event['previousKey']);
+        $this->assertEquals('anonymousUser', $event['previousContextKind']);
+    }
+
     public function testEventsAreNotPublishedIfSendEventsIsFalse()
     {
         // In order to do this test, we cannot provide a mock object for Event_Processor_,