diff --git a/.circleci/config.yml b/.circleci/config.yml
new file mode 100644
index 000000000..159bc0e79
--- /dev/null
+++ b/.circleci/config.yml
@@ -0,0 +1,98 @@
+version: 2
+
+workflows:
+  version: 2
+  test:
+    jobs:
+      - test-5.5
+      - test-5.6
+      - test-7.0
+      - test-7.1
+      - test-7.2
+      - integration-test
+
+php-docker-template: &php-docker-template
+  steps:
+    - checkout
+    - run:
+        name: install current dependencies
+        command: composer install --no-progress
+    - run:
+        name: run tests with current dependency versions
+        command: vendor/bin/phpunit --log-junit ~/phpunit/junit.xml --coverage-text tests
+    - store_test_results:
+        path: ~/phpunit
+    - store_artifacts:
+        path: ~/phpunit
+    - run:
+        name: run tests with highest available dependency versions
+        command: composer update --no-progress && vendor/bin/phpunit tests
+    - run:
+        name: run tests with lowest available dependency versions
+        # we skip this for 7.2 because the lowest compatible version of PHPUnit has a bug:
+        # https://github.com/sebastianbergmann/comparator/pull/30
+        command: |
+          if [[ $CIRCLE_JOB != test-7.2 ]]; then
+            composer update --prefer-lowest --no-progress && vendor/bin/phpunit tests;
+          fi
+
+jobs:
+  test-5.6:
+    <<: *php-docker-template
+    docker:
+      - image: circleci/php:5.6.34-cli-jessie
+  test-7.0:
+    <<: *php-docker-template
+    docker:
+      - image: circleci/php:7.0.28-cli-jessie
+  test-7.1:
+    <<: *php-docker-template
+    docker:
+      - image: circleci/php:7.1.15-cli-jessie
+  test-7.2:
+    <<: *php-docker-template
+    docker:
+      - image: circleci/php:7.2.3-cli-stretch
+
+  test-5.5: # CircleCI doesn't provide a Docker image for 5.5
+    machine:
+      image: circleci/classic:latest # Ubuntu 14.04
+    steps:
+      - run:
+          name: install PHP and Composer
+          command: |
+            sudo apt-get update &&
+            sudo apt-get install circleci-php-5.5.36 &&
+            php -r "copy('https://getcomposer.org/installer', '/tmp/composer-setup.php');" &&
+            sudo php /tmp/composer-setup.php --install-dir=/usr/local/bin --filename=composer
+      - checkout
+      - run:
+          name: update dependencies # the dependencies in composer.lock don't work with 5.5
+          command: composer update --no-progress
+      - run:
+          name: run tests
+          command: vendor/bin/phpunit --log-junit ~/phpunit/junit.xml --coverage-text tests
+      - store_test_results:
+          path: ~/phpunit
+      - store_artifacts:
+          path: ~/phpunit
+
+  integration-test:
+    docker:
+      - image: circleci/php:5.6.34-cli-jessie
+      - image: redis
+    steps:
+      - checkout
+      - run:
+          name: setup apcu
+          command: |
+            pecl config-set php_ini /usr/local/etc/php/php.ini
+            yes '' | sudo pecl install -f apcu-4.0.10 || true;
+            echo "extension=apcu.so" | sudo tee -a /usr/local/etc/php/conf.d/apcu.ini;
+            echo "apc.enable_cli = 1" | sudo tee -a /usr/local/etc/php/conf.d/apcu.ini
+      - run: composer update --no-progress
+      - run: vendor/bin/phpunit --log-junit ~/phpunit/junit.xml integration-tests/LDDFeatureRequesterTest.php
+      - store_test_results:
+          path: ~/phpunit
+      - store_artifacts:
+          path: ~/phpunit
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9766e60a7..a9c853cd4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,12 @@
 
 All notable changes to the LaunchDarkly PHP SDK will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [3.1.0] - 2018-04-30
+### Added
+- Analytics events for feature evaluations now have a `variation` property (the variation index) as well as `value`. This will allow for better performance in future versions of [`ld-relay`](https://github.com/launchdarkly/ld-relay) when it is used with the PHP client.
+### Fixed
+- Fixed a bug that made segment-based rules always fall through when using `LDDFeatureRequester`.
+
 ## [3.0.0] - 2018-02-21
 ### Added
 - Support for a new LaunchDarkly feature: reusable user segments.
diff --git a/README.md b/README.md
index 368d8ed30..8871b609e 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,6 @@
 LaunchDarkly SDK for PHP
 ===========================
 
-[![Code Climate](https://codeclimate.com/github/launchdarkly/php-client/badges/gpa.svg)](https://codeclimate.com/github/launchdarkly/php-client)
-
 [![Circle CI](https://circleci.com/gh/launchdarkly/php-client.svg?style=svg)](https://circleci.com/gh/launchdarkly/php-client)
 
 Requirements
diff --git a/VERSION b/VERSION
index 4a36342fc..fd2a01863 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.0.0
+3.1.0
diff --git a/circle.yml b/circle.yml
deleted file mode 100644
index c3bc0437b..000000000
--- a/circle.yml
+++ /dev/null
@@ -1,31 +0,0 @@
-machine:
-  php:
-    version: 5.6.14
-  services:
-      - redis
-      - docker
-dependencies:
-  pre:
-    - yes '' | pecl install -f apcu-4.0.10
-    - echo "extension=apcu.so" >> $(php-config --prefix)/etc/conf.d/apcu.ini
-    - echo "apc.enable_cli = 1" >> $(php-config --prefix)/etc/conf.d/apcu.ini
-    - docker pull php
-    - docker pull nyanpass/php5.5
-
-test:
-  override:
-    - vendor/bin/phpunit tests --coverage-text
-    - vendor/bin/phpunit integration-tests/LDDFeatureRequesterTest.php
-
-    - composer update && vendor/bin/phpunit tests
-    - composer update --prefer-lowest && vendor/bin/phpunit tests
-
-    - docker run -it -v `pwd`:/php-client php:7.0-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update && vendor/bin/phpunit"
-    - docker run -it -v `pwd`:/php-client php:7.0-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update --prefer-lowest && vendor/bin/phpunit"
-
-    - docker run -it -v `pwd`:/php-client php:7.1-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update && vendor/bin/phpunit"
-    - docker run -it -v `pwd`:/php-client php:7.1-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update --prefer-lowest && vendor/bin/phpunit"
-
-    - docker run -it -v `pwd`:/php-client nyanpass/php5.5:5.5-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update && vendor/bin/phpunit"
-    - docker run -it -v `pwd`:/php-client nyanpass/php5.5:5.5-alpine sh -c "curl -s https://getcomposer.org/installer | php && cd /php-client && /composer.phar update --prefer-lowest && vendor/bin/phpunit"
-
diff --git a/src/LaunchDarkly/CurlEventPublisher.php b/src/LaunchDarkly/CurlEventPublisher.php
index d731377eb..1151b0494 100644
--- a/src/LaunchDarkly/CurlEventPublisher.php
+++ b/src/LaunchDarkly/CurlEventPublisher.php
@@ -60,6 +60,7 @@ private function createArgs($payload)
         $args.= " -H 'Content-Type: application/json'";
         $args.= " -H " . escapeshellarg("Authorization: " . $this->_sdkKey);
         $args.= " -H 'User-Agent: PHPClient/" . LDClient::VERSION . "'";
+        $args.= " -H 'X-LaunchDarkly-Event-Schema: " . EventPublisher::CURRENT_SCHEMA_VERSION . "'";
         $args.= " -H 'Accept: application/json'";
         $args.= " -d " . escapeshellarg($payload);
         $args.= " " . escapeshellarg($scheme . $this->_host . ":" . $this->_port . $this->_path . "/bulk");
diff --git a/src/LaunchDarkly/EventPublisher.php b/src/LaunchDarkly/EventPublisher.php
index 38a344974..38dd94f44 100644
--- a/src/LaunchDarkly/EventPublisher.php
+++ b/src/LaunchDarkly/EventPublisher.php
@@ -6,6 +6,8 @@
  */
 interface EventPublisher
 {
+    const CURRENT_SCHEMA_VERSION = 2;
+
     /**
      * @param string $sdkKey The SDK key for your account
      * @param mixed[] $options Client configuration settings
diff --git a/src/LaunchDarkly/FeatureFlag.php b/src/LaunchDarkly/FeatureFlag.php
index 0ac89d317..1bc81855d 100644
--- a/src/LaunchDarkly/FeatureFlag.php
+++ b/src/LaunchDarkly/FeatureFlag.php
@@ -95,18 +95,18 @@ public function evaluate($user, $featureRequester)
         if ($this->isOn()) {
             $result = $this->_evaluate($user, $featureRequester, $prereqEvents);
             if ($result !== null) {
-                return new EvalResult($result, $prereqEvents);
+                return $result;
             }
         }
-        $offVariation = $this->getOffVariationValue();
-        return new EvalResult($offVariation, $prereqEvents);
+        $offVariationValue = $this->getOffVariationValue();
+        return new EvalResult($this->_offVariation, $offVariationValue, $prereqEvents);
     }
 
     /**
      * @param $user LDUser
      * @param $featureRequester FeatureRequester
      * @param $events
-     * @return mixed|null
+     * @return EvalResult|null
      */
     private function _evaluate($user, $featureRequester, &$events)
     {
@@ -120,21 +120,26 @@ private function _evaluate($user, $featureRequester, &$events)
                         return null;
                     } elseif ($prereqFeatureFlag->isOn()) {
                         $prereqEvalResult = $prereqFeatureFlag->_evaluate($user, $featureRequester, $events);
-                        $variation = $prereqFeatureFlag->getVariation($prereq->getVariation());
-                        if ($prereqEvalResult === null || $variation === null || $prereqEvalResult !== $variation) {
+                        $variation = $prereq->getVariation();
+                        if ($prereqEvalResult === null || $variation === null || $prereqEvalResult->getVariation() !== $variation) {
                             $prereqOk = false;
                         }
                     } else {
                         $prereqOk = false;
                     }
-                    array_push($events, Util::newFeatureRequestEvent($prereqFeatureFlag->getKey(), $user, $prereqEvalResult, null, $prereqFeatureFlag->getVersion(), $this->_key));
+                    array_push($events, Util::newFeatureRequestEvent($prereqFeatureFlag->getKey(), $user,
+                        $prereqEvalResult === null ? null : $prereqEvalResult->getVariation(),
+                        $prereqEvalResult === null ? null : $prereqEvalResult->getValue(),
+                        null, $prereqFeatureFlag->getVersion(), $this->_key));
                 } catch (EvaluationException $e) {
                     $prereqOk = false;
                 }
             }
         }
         if ($prereqOk) {
-            return $this->getVariation($this->evaluateIndex($user, $featureRequester));
+            $variation = $this->evaluateIndex($user, $featureRequester);
+            $value = $this->getVariation($variation);
+            return new EvalResult($variation, $value, $events);
         }
         return null;
     }
@@ -221,6 +226,7 @@ public function isDeleted()
 
 class EvalResult
 {
+    private $_variation = null;
     private $_value = null;
     /** @var array */
     private $_prerequisiteEvents = [];
@@ -230,12 +236,21 @@ class EvalResult
      * @param null $value
      * @param array $prerequisiteEvents
      */
-    public function __construct($value, array $prerequisiteEvents)
+    public function __construct($variation, $value, array $prerequisiteEvents)
     {
+        $this->_variation = $variation;
         $this->_value = $value;
         $this->_prerequisiteEvents = $prerequisiteEvents;
     }
 
+    /**
+     * @return int
+     */
+    public function getVariation()
+    {
+        return $this->_variation;
+    }
+
     /**
      * @return null
      */
diff --git a/src/LaunchDarkly/GuzzleEventPublisher.php b/src/LaunchDarkly/GuzzleEventPublisher.php
index ca9942542..ce18f0f14 100644
--- a/src/LaunchDarkly/GuzzleEventPublisher.php
+++ b/src/LaunchDarkly/GuzzleEventPublisher.php
@@ -39,7 +39,8 @@ public function __construct($sdkKey, array $options = array())
                 'Content-Type'  => 'application/json',
                 'Authorization' => $this->_sdkKey,
                 'User-Agent'    => 'PHPClient/' . LDClient::VERSION,
-                'Accept'        => 'application/json'
+                'Accept'        => 'application/json',
+                'X-LaunchDarkly-Event-Schema' => strval(EventPublisher::CURRENT_SCHEMA_VERSION)
             ],
             'timeout' => $options['timeout'],
             'connect_timeout' => $options['connect_timeout']
diff --git a/src/LaunchDarkly/LDClient.php b/src/LaunchDarkly/LDClient.php
index fc21d080d..3604db65f 100644
--- a/src/LaunchDarkly/LDClient.php
+++ b/src/LaunchDarkly/LDClient.php
@@ -19,7 +19,7 @@ class LDClient
 {
     const DEFAULT_BASE_URI = 'https://app.launchdarkly.com';
     const DEFAULT_EVENTS_URI = 'https://events.launchdarkly.com';
-    const VERSION = '3.0.0';
+    const VERSION = '3.1.0';
 
     /** @var string */
     protected $_sdkKey;
@@ -148,12 +148,7 @@ public function variation($key, $user, $default = false)
         }
 
         try {
-            if (is_null($user) || is_null($user->getKey())) {
-                $this->_sendFlagRequestEvent($key, $user, $default, $default);
-                $this->_logger->warning("Variation called with null user or null user key! Returning default value");
-                return $default;
-            }
-            if ($user->isKeyBlank()) {
+            if (!is_null($user) && $user->isKeyBlank()) {
                 $this->_logger->warning("User key is blank. Flag evaluation will proceed, but the user will not be stored in LaunchDarkly.");
             }
             try {
@@ -164,7 +159,12 @@ public function variation($key, $user, $default = false)
             }
 
             if (is_null($flag)) {
-                $this->_sendFlagRequestEvent($key, $user, $default, $default);
+                $this->_sendFlagRequestEvent($key, $user, null, $default, $default);
+                return $default;
+            }
+            if (is_null($user) || is_null($user->getKey())) {
+                $this->_sendFlagRequestEvent($key, $user, null, $default, $default, $flag->getVersion());
+                $this->_logger->warning("Variation called with null user or null user key! Returning default value");
                 return $default;
             }
             $evalResult = $flag->evaluate($user, $this->_featureRequester);
@@ -173,15 +173,18 @@ public function variation($key, $user, $default = false)
                     $this->_eventProcessor->enqueue($e);
                 }
             }
-            if ($evalResult->getValue() !== null) {
-                $this->_sendFlagRequestEvent($key, $user, $evalResult->getValue(), $default, $flag->getVersion());
+            if ($evalResult !== null && $evalResult->getValue() !== null) {
+                $this->_sendFlagRequestEvent($key, $user, $evalResult->getVariation(), $evalResult->getValue(), $default, $flag->getVersion());
                 return $evalResult->getValue();
+            } else {
+                $this->_sendFlagRequestEvent($key, $user, null, $default, $default, $flag->getVersion());
+                return $default;
             }
         } catch (\Exception $e) {
             $this->_logger->error("Caught $e");
         }
         try {
-            $this->_sendFlagRequestEvent($key, $user, $default, $default);
+            $this->_sendFlagRequestEvent($key, $user, null, $default, $default);
         } catch (\Exception $e) {
             $this->_logger->error("Caught $e");
         }
@@ -326,17 +329,18 @@ public function flush()
     /**
      * @param $key string
      * @param $user LDUser
+     * @param $variation int | null
      * @param $value mixed
      * @param $default
      * @param $version int | null
      * @param string | null $prereqOf
      */
-    protected function _sendFlagRequestEvent($key, $user, $value, $default, $version = null, $prereqOf = null)
+    protected function _sendFlagRequestEvent($key, $user, $variation, $value, $default, $version = null, $prereqOf = null)
     {
         if ($this->isOffline() || !$this->_send_events) {
             return;
         }
-        $this->_eventProcessor->enqueue(Util::newFeatureRequestEvent($key, $user, $value, $default, $version, $prereqOf));
+        $this->_eventProcessor->enqueue(Util::newFeatureRequestEvent($key, $user, $variation, $value, $default, $version, $prereqOf));
     }
 
     protected function _get_default($key, $default)
diff --git a/src/LaunchDarkly/LDDFeatureRequester.php b/src/LaunchDarkly/LDDFeatureRequester.php
index 4ae4ecb44..1058f54ca 100644
--- a/src/LaunchDarkly/LDDFeatureRequester.php
+++ b/src/LaunchDarkly/LDDFeatureRequester.php
@@ -98,7 +98,7 @@ public function getSegment($key)
         $raw = $this->get_from_cache($this->_segments_key, $key);
         if ($raw === null) {
             $redis = $this->get_connection();
-            $raw = $redis->hget($this->_features_key, $key);
+            $raw = $redis->hget($this->_segments_key, $key);
             if ($raw) {
                 $this->store_in_cache($this->_segments_key, $key, $raw);
             }
diff --git a/src/LaunchDarkly/Util.php b/src/LaunchDarkly/Util.php
index 231f4b47c..6ab2ae28c 100644
--- a/src/LaunchDarkly/Util.php
+++ b/src/LaunchDarkly/Util.php
@@ -37,10 +37,11 @@ public static function currentTimeUnixMillis()
      * @param null $prereqOf string | null
      * @return array
      */
-    public static function newFeatureRequestEvent($key, $user, $value, $default, $version = null, $prereqOf = null)
+    public static function newFeatureRequestEvent($key, $user, $variation, $value, $default, $version = null, $prereqOf = null)
     {
         $event = array();
         $event['user'] = $user;
+        $event['variation'] = $variation;
         $event['value'] = $value;
         $event['kind'] = "feature";
         $event['creationDate'] = Util::currentTimeUnixMillis();
diff --git a/tests/FeatureFlagTest.php b/tests/FeatureFlagTest.php
index 8b8dde742..51f865b08 100644
--- a/tests/FeatureFlagTest.php
+++ b/tests/FeatureFlagTest.php
@@ -193,6 +193,308 @@ public function testDecodeMulti(array $feature)
         self::assertInstanceOf(FeatureFlag::class, $featureFlag);
     }
 
+    public function testFlagReturnsOffVariationIfFlagIsOff()
+    {
+        $flagJson = array(
+            'key' => 'feature',
+            'version' => 1,
+            'deleted' => false,
+            'on' => false,
+            'targets' => array(),
+            'prerequisites' => array(),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag = FeatureFlag::decode($flagJson);
+        $ub = new LDUserBuilder('x');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(1, $result->getVariation());
+        self::assertEquals('off', $result->getValue());
+        self::assertEquals(array(), $result->getPrerequisiteEvents());
+    }
+
+    public function testFlagReturnsNullIfFlagIsOffAndOffVariationIsUnspecified()
+    {
+        $flagJson = array(
+            'key' => 'feature',
+            'version' => 1,
+            'deleted' => false,
+            'on' => false,
+            'targets' => array(),
+            'prerequisites' => array(),
+            'rules' => array(),
+            'offVariation' => null,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag = FeatureFlag::decode($flagJson);
+        $ub = new LDUserBuilder('x');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertNull($result->getVariation());
+        self::assertNull($result->getValue());
+        self::assertEquals(array(), $result->getPrerequisiteEvents());
+    }
+
+    public function testFlagReturnsOffVariationIfPrerequisiteIsNotFound()
+    {
+        $flagJson = array(
+            'key' => 'feature0',
+            'version' => 1,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(
+                array('key' => 'feature1', 'variation' => 1)
+            ),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag = FeatureFlag::decode($flagJson);
+        $ub = new LDUserBuilder('x');
+        $user = $ub->build();
+        $requester = new MockFeatureRequesterForFeature();
+
+        $result = $flag->evaluate($user, $requester);
+        self::assertEquals(1, $result->getVariation());
+        self::assertEquals('off', $result->getValue());
+        self::assertEquals(array(), $result->getPrerequisiteEvents());
+    }
+
+    public function testFlagReturnsOffVariationAndEventIfPrerequisiteIsNotMet()
+    {
+        $flag0Json = array(
+            'key' => 'feature0',
+            'version' => 1,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(
+                array('key' => 'feature1', 'variation' => 1)
+            ),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag1Json = array(
+            'key' => 'feature1',
+            'version' => 2,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('nogo', 'go'),
+            'salt' => ''
+        );
+        $flag0 = FeatureFlag::decode($flag0Json);
+        $flag1 = FeatureFlag::decode($flag1Json);
+        $ub = new LDUserBuilder('x');
+        $user = $ub->build();
+        $requester = new MockFeatureRequesterForFeature();
+        $requester->key = $flag1->getKey();
+        $requester->val = $flag1;
+
+        $result = $flag0->evaluate($user, $requester);
+        self::assertEquals(1, $result->getVariation());
+        self::assertEquals('off', $result->getValue());
+
+        $events = $result->getPrerequisiteEvents();
+        self::assertEquals(1, count($events));
+        $event = $events[0];
+        self::assertEquals('feature', $event['kind']);
+        self::assertEquals($flag1->getKey(), $event['key']);
+        self::assertEquals('nogo', $event['value']);
+        self::assertEquals($flag1->getVersion(), $event['version']);
+        self::assertEquals($flag0->getKey(), $event['prereqOf']);
+    }
+
+    public function testFlagReturnsFallthroughVariationAndEventIfPrerequisiteIsMetAndThereAreNoRules()
+    {
+        $flag0Json = array(
+            'key' => 'feature0',
+            'version' => 1,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(
+                array('key' => 'feature1', 'variation' => 1)
+            ),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag1Json = array(
+            'key' => 'feature1',
+            'version' => 2,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 1),
+            'variations' => array('nogo', 'go'),
+            'salt' => ''
+        );
+        $flag0 = FeatureFlag::decode($flag0Json);
+        $flag1 = FeatureFlag::decode($flag1Json);
+        $ub = new LDUserBuilder('x');
+        $user = $ub->build();
+        $requester = new MockFeatureRequesterForFeature();
+        $requester->key = $flag1->getKey();
+        $requester->val = $flag1;
+
+        $result = $flag0->evaluate($user, $requester);
+        self::assertEquals(0, $result->getVariation());
+        self::assertEquals('fall', $result->getValue());
+
+        $events = $result->getPrerequisiteEvents();
+        self::assertEquals(1, count($events));
+        $event = $events[0];
+        self::assertEquals('feature', $event['kind']);
+        self::assertEquals($flag1->getKey(), $event['key']);
+        self::assertEquals('go', $event['value']);
+        self::assertEquals($flag1->getVersion(), $event['version']);
+        self::assertEquals($flag0->getKey(), $event['prereqOf']);
+    }
+
+    public function testFlagMatchesUserFromTargets()
+    {
+        $flagJson = array(
+            'key' => 'feature',
+            'version' => 1,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(
+                array('values' => array('whoever', 'userkey'), 'variation' => 2)
+            ),
+            'prerequisites' => array(),
+            'rules' => array(),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag = FeatureFlag::decode($flagJson);
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(2, $result->getVariation());
+        self::assertEquals('on', $result->getValue());
+        self::assertEquals(array(), $result->getPrerequisiteEvents());
+    }
+
+    public function testFlagMatchesUserFromRules()
+    {
+        $flagJson = array(
+            'key' => 'feature',
+            'version' => 1,
+            'deleted' => false,
+            'on' => true,
+            'targets' => array(),
+            'prerequisites' => array(),
+            'rules' => array(
+                array(
+                    'clauses' => array(
+                        array(
+                            'attribute' => 'key',
+                            'op' => 'in',
+                            'values' => array('userkey'),
+                            'negate' => false
+                        )
+                    ),
+                    'variation' => 2
+                )
+            ),
+            'offVariation' => 1,
+            'fallthrough' => array('variation' => 0),
+            'variations' => array('fall', 'off', 'on'),
+            'salt' => ''
+        );
+        $flag = FeatureFlag::decode($flagJson);
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(2, $result->getVariation());
+        self::assertEquals('on', $result->getValue());
+        self::assertEquals(array(), $result->getPrerequisiteEvents());
+    }
+
+    public function clauseCanMatchBuiltInAttribute()
+    {
+        $clause = array('attribute' => 'name', 'op' => 'in', 'values' => array('Bob'), 'negate' => false);
+        $flag = $this->booleanFlagWithClauses(array($clause));
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(true, $result->getValue());
+    }
+
+    public function clauseCanMatchCustomAttribute()
+    {
+        $clause = array('attribute' => 'legs', 'op' => 'in', 'values' => array('4'), 'negate' => false);
+        $flag = $this->booleanFlagWithClauses(array($clause));
+        $ub = new LDUserBuilder('userkey');
+        $ub->customAttribute('legs', 4);
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(true, $result->getValue());
+    }
+
+    public function clauseReturnsFalseForMissingAttribute()
+    {
+        $clause = array('attribute' => 'legs', 'op' => 'in', 'values' => array('4'), 'negate' => false);
+        $flag = $this->booleanFlagWithClauses(array($clause));
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(false, $result->getValue());
+    }
+
+    public function clauseCanBeNegated()
+    {
+        $clause = array('attribute' => 'name', 'op' => 'in', 'values' => array('Bob'), 'negate' => true);
+        $flag = $this->booleanFlagWithClauses(array($clause));
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(false, $result->getValue());
+    }
+
+    public function clauseWithUnknownOperatorDoesNotMatch()
+    {
+        $clause = array('attribute' => 'name', 'op' => 'doesSomethingUnsupported', 'values' => array('Bob'), 'negate' => false);
+        $flag = $this->booleanFlagWithClauses(array($clause));
+        $ub = new LDUserBuilder('userkey');
+        $user = $ub->build();
+
+        $result = $flag->evaluate($user, null);
+        self::assertEquals(false, $result->getValue());
+    }
+
     public function testSegmentMatchClauseRetrievesSegmentFromStore()
     {
         $segmentJson = array(
@@ -234,7 +536,7 @@ public function testSegmentMatchClauseFallsThroughWithNoErrorsIfSegmentNotFound(
         self::assertFalse($result->getValue());
     }
 
-    private function makeBooleanFeatureWithSegmentMatch($segmentKey)
+    private function booleanFlagWithClauses($clauses)
     {
         $featureJson = array(
             'key' => 'test',
@@ -244,17 +546,7 @@ private function makeBooleanFeatureWithSegmentMatch($segmentKey)
             'variations' => array(false, true),
             'fallthrough' => array('variation' => 0),
             'rules' => array(
-                array(
-                    'clauses' => array(
-                        array(
-                            'attribute' => '',
-                            'op' => 'segmentMatch',
-                            'values' => array($segmentKey),
-                            'negate' => false
-                        )
-                    ),
-                    'variation' => 1
-                )
+                array('clauses' => $clauses, 'variation' => 1)
             ),
             'offVariation' => 0,
             'prerequisites' => array(),
@@ -263,8 +555,43 @@ private function makeBooleanFeatureWithSegmentMatch($segmentKey)
         );
         return FeatureFlag::decode($featureJson);
     }
+
+    private function makeBooleanFeatureWithSegmentMatch($segmentKey)
+    {
+        $clause = array(
+            'attribute' => '',
+            'op' => 'segmentMatch',
+            'values' => array($segmentKey),
+            'negate' => false
+        );
+        return $this->booleanFlagWithClauses(array($clause));
+    }
 }
 
+class MockFeatureRequesterForFeature implements FeatureRequester
+{
+    public $key = null;
+    public $val = null;
+
+    function __construct($baseurl = null, $key = null, $options = null)
+    {
+    }
+
+    public function getFeature($key)
+    {
+        return ($key == $this->key) ? $this->val : null;
+    }
+
+    public function getSegment($key)
+    {
+        return null;
+    }
+
+    public function getAllFeatures()
+    {
+        return null;
+    }
+}
 
 class MockFeatureRequesterForSegment implements FeatureRequester
 {