diff --git a/composer.json b/composer.json
index 7a672af0..607d2c41 100644
--- a/composer.json
+++ b/composer.json
@@ -11,15 +11,15 @@
   ],
   "require": {
     "php": ">=5.5",
-    "justinrainbow/json-schema": "^1.6 || ^2.0 || ^4.0",
+    "justinrainbow/json-schema": "^1.6 || ^2.0 || ^4.0 || ^5.0",
     "lastguest/murmurhash": "1.3.0",
     "guzzlehttp/guzzle": "~5.3|~6.2",
     "monolog/monolog": "~1.21",
     "icecave/parity": "^1.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "~4.8|~5.0",
-    "satooshi/php-coveralls": "v1.0.1"
+    "phpunit/phpunit": "^4.8|^5.0",
+    "php-coveralls/php-coveralls": "v2.0.0"
   },
   "autoload": {
     "psr-4": {
diff --git a/src/Optimizely/Event/Builder/EventBuilder.php b/src/Optimizely/Event/Builder/EventBuilder.php
index 8ed82999..1eaceff7 100644
--- a/src/Optimizely/Event/Builder/EventBuilder.php
+++ b/src/Optimizely/Event/Builder/EventBuilder.php
@@ -180,45 +180,50 @@ private function getImpressionParams(Experiment $experiment, $variationId)
     private function getConversionParams($config, $eventKey, $experimentVariationMap, $eventTags)
     {
         $conversionParams = [];
+        $singleSnapshot = [];
+        $decisions = [];
+
         foreach ($experimentVariationMap as $experimentId => $variationId) {
-            $singleSnapshot = [];
+            
+            
             $experiment = $config->getExperimentFromId($experimentId);
             $eventEntity = $config->getEvent($eventKey);
 
-            $singleSnapshot[DECISIONS] = [
-                [
-                    CAMPAIGN_ID => $experiment->getLayerId(),
-                    EXPERIMENT_ID => $experiment->getId(),
-                    VARIATION_ID => $variationId
-                ]
-            ];
-
-            $singleSnapshot[EVENTS] = [
-                [
-                    ENTITY_ID => $eventEntity->getId(),
-                    TIMESTAMP => time()*1000,
-                    UUID => GeneratorUtils::getRandomUuid(),
-                    KEY => $eventKey
-                ]
+            $decision = [                
+                CAMPAIGN_ID => $experiment->getLayerId(),
+                EXPERIMENT_ID => $experiment->getId(),
+                VARIATION_ID => $variationId                
             ];
+            $decisions [] = $decision;
+        }
 
-            if (!is_null($eventTags)) {
-                $revenue = EventTagUtils::getRevenueValue($eventTags, $this->_logger);
-                if (!is_null($revenue)) {
-                    $singleSnapshot[EVENTS][0][EventTagUtils::REVENUE_EVENT_METRIC_NAME] = $revenue;
-                }
+        $eventDict = [
+            ENTITY_ID => $eventEntity->getId(),
+            TIMESTAMP => time()*1000,
+            UUID => GeneratorUtils::getRandomUuid(),
+            KEY => $eventKey            
+        ];
 
-                $eventValue = EventTagUtils::getNumericValue($eventTags, $this->_logger);
-                if (!is_null($eventValue)) {
-                    $singleSnapshot[EVENTS][0][EventTagUtils::NUMERIC_EVENT_METRIC_NAME] = $eventValue;
-                }
+        if (!is_null($eventTags)) {
+            $revenue = EventTagUtils::getRevenueValue($eventTags, $this->_logger);
+            if (!is_null($revenue)) {
+                $eventDict[EventTagUtils::REVENUE_EVENT_METRIC_NAME] = $revenue;
+            }
 
-                $singleSnapshot[EVENTS][0]['tags'] = $eventTags;
+            $eventValue = EventTagUtils::getNumericValue($eventTags, $this->_logger);
+            if (!is_null($eventValue)) {
+                $eventDict[EventTagUtils::NUMERIC_EVENT_METRIC_NAME] = $eventValue;
             }
 
-            $conversionParams [] = $singleSnapshot;
+            if(count($eventTags) > 0) {
+                $eventDict['tags'] = $eventTags;
+            }            
         }
 
+        $singleSnapshot[DECISIONS] = $decisions;
+        $singleSnapshot[EVENTS] [] = $eventDict;
+        $conversionParams [] = $singleSnapshot;
+
         return $conversionParams;
     }
 
diff --git a/src/Optimizely/Exceptions/InvalidDatafileVersionException.php b/src/Optimizely/Exceptions/InvalidDatafileVersionException.php
new file mode 100644
index 00000000..a5681b90
--- /dev/null
+++ b/src/Optimizely/Exceptions/InvalidDatafileVersionException.php
@@ -0,0 +1,22 @@
+<?php
+/**
+ * Copyright 2018, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+namespace Optimizely\Exceptions;
+
+class InvalidDatafileVersionException extends OptimizelyException
+{
+}
diff --git a/src/Optimizely/Optimizely.php b/src/Optimizely/Optimizely.php
index 4a0946ab..803ae0be 100644
--- a/src/Optimizely/Optimizely.php
+++ b/src/Optimizely/Optimizely.php
@@ -18,7 +18,9 @@
 
 use Exception;
 use Optimizely\Exceptions\InvalidAttributeException;
+use Optimizely\Exceptions\InvalidDatafileVersionException;
 use Optimizely\Exceptions\InvalidEventTagException;
+use Optimizely\Exceptions\InvalidInputException;
 use Throwable;
 use Monolog\Logger;
 use Optimizely\DecisionService\DecisionService;
@@ -36,6 +38,7 @@
 use Optimizely\Notification\NotificationCenter;
 use Optimizely\Notification\NotificationType;
 use Optimizely\UserProfile\UserProfileServiceInterface;
+use Optimizely\Utils\Errors;
 use Optimizely\Utils\Validator;
 use Optimizely\Utils\VariableTypeUtils;
 
@@ -120,15 +123,14 @@ public function __construct(
 
         try {
             $this->_config = new ProjectConfig($datafile, $this->_logger, $this->_errorHandler);
-        } catch (Throwable $exception) {
-            $this->_isValid = false;
-            $this->_logger = new DefaultLogger();
-            $this->_logger->log(Logger::ERROR, 'Provided "datafile" is in an invalid format.');
-            return;
         } catch (Exception $exception) {
             $this->_isValid = false;
-            $this->_logger = new DefaultLogger();
-            $this->_logger->log(Logger::ERROR, 'Provided "datafile" is in an invalid format.');
+            $defaultLogger = new DefaultLogger();
+            $errorMsg = $exception->getCode() == InvalidDatafileVersionException::class ? $exception->getMessage() : sprintf(Errors::INVALID_FORMAT, 'datafile');
+            $errorToHandle = $exception->getCode() == InvalidDatafileVersionException::class ? new InvalidDatafileVersionException($errorMsg) : new InvalidInputException($errorMsg);
+            $defaultLogger->log(Logger::ERROR, $errorMsg);
+            $this->_logger->log(Logger::ERROR, $errorMsg);
+            $this->_errorHandler->handleError($errorToHandle);
             return;
         }
 
@@ -728,4 +730,17 @@ public function getFeatureVariableString($featureFlagKey, $variableKey, $userId,
 
         return $variableValue;
     }
+
+    /**
+     * Determine if the instance of the Optimizely client is valid.
+     * An instance can be deemed invalid if it was not initialized
+     * properly due to an invalid datafile being passed in.
+     *
+     * @return True if the Optimizely instance is valid.
+     *         False if the Optimizely instance is not valid.
+     */
+    public function isValid()
+    {
+        return $this->_isValid;
+    }
 }
diff --git a/src/Optimizely/ProjectConfig.php b/src/Optimizely/ProjectConfig.php
index 757b28c4..256da1c4 100644
--- a/src/Optimizely/ProjectConfig.php
+++ b/src/Optimizely/ProjectConfig.php
@@ -31,6 +31,7 @@
 use Optimizely\ErrorHandler\ErrorHandlerInterface;
 use Optimizely\Exceptions\InvalidAttributeException;
 use Optimizely\Exceptions\InvalidAudienceException;
+use Optimizely\Exceptions\InvalidDatafileVersionException;
 use Optimizely\Exceptions\InvalidEventException;
 use Optimizely\Exceptions\InvalidExperimentException;
 use Optimizely\Exceptions\InvalidFeatureFlagException;
@@ -50,6 +51,9 @@
 class ProjectConfig
 {
     const RESERVED_ATTRIBUTE_PREFIX = '$opt_';
+    const V2 = '2';
+    const V3 = '3';
+    const V4 = '4';
 
     /**
      * @var string Version of the datafile.
@@ -185,10 +189,17 @@ class ProjectConfig
      */
     public function __construct($datafile, $logger, $errorHandler)
     {
+        $supportedVersions = array(self::V2, self::V3, self::V4);
         $config = json_decode($datafile, true);
         $this->_logger = $logger;
         $this->_errorHandler = $errorHandler;
         $this->_version = $config['version'];
+        if(!in_array($this->_version, $supportedVersions)){
+            throw new InvalidDatafileVersionException(
+                "This version of the PHP SDK does not support the given datafile version: {$this->_version}."
+            );
+        }
+
         $this->_accountId = $config['accountId'];
         $this->_projectId = $config['projectId'];
         $this->_anonymizeIP = isset($config['anonymizeIP'])? $config['anonymizeIP'] : false;
diff --git a/src/Optimizely/Utils/Errors.php b/src/Optimizely/Utils/Errors.php
new file mode 100644
index 00000000..ec0d1d33
--- /dev/null
+++ b/src/Optimizely/Utils/Errors.php
@@ -0,0 +1,21 @@
+<?php
+/**
+ * Copyright 2018, Optimizely
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+namespace Optimizely\Utils;
+ class Errors
+{
+    const INVALID_FORMAT = 'Provided %s is in an invalid format.';
+}
diff --git a/tests/EventTests/EventBuilderTest.php b/tests/EventTests/EventBuilderTest.php
index 5f4ae8fc..367b1420 100644
--- a/tests/EventTests/EventBuilderTest.php
+++ b/tests/EventTests/EventBuilderTest.php
@@ -823,4 +823,70 @@ public function testCreateConversionEventWithUserAgentAttribute()
         $result = $this->areLogEventsEqual($expectedLogEvent, $logEvent);
         $this->assertTrue($result[0], $result[1]);
     }
+
+    public function testCreateConversionEventWhenEventUsedInMultipleExp()
+    {  
+        $eventTags = [
+            'revenue' => 4200,
+            'value' => 1.234,
+            'non-revenue' => 'abc'
+        ];      
+        $this->expectedEventParams['visitors'][0]['snapshots'][0]['decisions'][] = [
+            'campaign_id' => '4',
+            'experiment_id' => '122230',
+            'variation_id' => '122234'
+        ];
+
+        $this->expectedEventParams['visitors'][0]['snapshots'][0]['events'][0] = [
+            'entity_id' => '7718020065',
+            'timestamp' => $this->timestamp,
+            'uuid' => $this->uuid,
+            'key' => 'multi_exp_event',
+            'revenue' => 4200,
+            'value' => 1.234,                    
+            'tags' => $eventTags,                        
+        ];
+        
+        array_unshift($this->expectedEventParams['visitors'][0]['attributes'],  
+            [                 
+                'entity_id' => '7723280020',
+                'key' => 'device_type',
+                'type' => 'custom',
+                'value' => 'iPhone'
+            ],[
+                'entity_id' => '7723340004',
+                'key' => 'location',
+                'type' => 'custom',
+                'value' => 'SF'
+            ]);
+        
+        $decisions = [
+            '7716830082' => '7721010009',
+            '122230' => '122234'
+        ];
+        $userAttributes = [
+            'device_type' => 'iPhone',
+            'location' => 'SF'
+        ];
+
+        $logEvent = $this->eventBuilder->createConversionEvent(
+                $this->config,
+                'multi_exp_event',
+                $decisions,
+                $this->testUserId,
+                $userAttributes,
+                $eventTags
+            );
+        $expectedLogEvent = new LogEvent(
+                $this->expectedEventUrl,
+                $this->expectedEventParams,
+                $this->expectedEventHttpVerb,
+                $this->expectedEventHeaders
+        );
+            
+        $logEvent = $this->fakeParamsToReconcile($logEvent);
+        $result = $this->areLogEventsEqual($expectedLogEvent, $logEvent);
+        $this->assertTrue($result[0], $result[1]);
+            
+    }
 }
diff --git a/tests/OptimizelyTest.php b/tests/OptimizelyTest.php
index 077a34d2..c81515e1 100644
--- a/tests/OptimizelyTest.php
+++ b/tests/OptimizelyTest.php
@@ -23,7 +23,9 @@
 use Optimizely\ErrorHandler\NoOpErrorHandler;
 use Optimizely\Event\LogEvent;
 use Optimizely\Exceptions\InvalidAttributeException;
+use Optimizely\Exceptions\InvalidDatafileVersionException;
 use Optimizely\Exceptions\InvalidEventTagException;
+use Optimizely\Exceptions\InvalidInputException;
 use Optimizely\Logger\NoOpLogger;
 use Optimizely\Notification\NotificationCenter;
 use Optimizely\Notification\NotificationType;
@@ -74,6 +76,18 @@ public function setUp()
             ->getMock();
     }
 
+    public function testIsValidForInvalidOptimizelyObject()
+    {
+        $optlyObject = new Optimizely('Random datafile');
+        $this->assertFalse($optlyObject->isValid());
+    }
+
+    public function testIsValidForValidOptimizelyObject()
+    {
+        $optlyObject = new Optimizely($this->datafile);
+        $this->assertTrue($optlyObject->isValid());
+    }
+
     public function testInitValidEventDispatcher()
     {
         $validDispatcher = new ValidEventDispatcher();
@@ -134,6 +148,42 @@ public function testInitInvalidErrorHandler()
         $this->fail('Unexpected behavior. Invalid error handler went through.');
     }
 
+    public function testInitUnSupportedDatafileVersion()
+    {
+        $errorHandlerMock = $this->getMockBuilder(NoOpErrorHandler::class)
+            ->setMethods(array('handleError'))
+            ->getMock();
+        $errorHandlerMock->expects($this->once())
+            ->method('handleError')
+            ->with(new InvalidDatafileVersionException('This version of the PHP SDK does not support the given datafile version: 5.'));
+        $optlyObject = new Optimizely(
+            UNSUPPORTED_DATAFILE,
+            null,
+            new DefaultLogger(Logger::INFO, self::OUTPUT_STREAM),
+            $errorHandlerMock,
+            true
+        );
+        $this->expectOutputRegex("/This version of the PHP SDK does not support the given datafile version: 5./");
+    }
+
+    public function testInitDatafileInvalidFormat()
+    {
+        $errorHandlerMock = $this->getMockBuilder(NoOpErrorHandler::class)
+            ->setMethods(array('handleError'))
+            ->getMock();
+        $errorHandlerMock->expects($this->once())
+            ->method('handleError')
+            ->with(new InvalidInputException('Provided datafile is in an invalid format.'));
+        $optlyObject = new Optimizely(
+            '{"version": "2"}',
+            null,
+            new DefaultLogger(Logger::INFO, self::OUTPUT_STREAM),
+            $errorHandlerMock,
+            true
+        );
+        $this->expectOutputRegex('/Provided datafile is in an invalid format./');
+    }
+
     public function testValidateDatafileInvalidFileJsonValidationNotSkipped()
     {
         $validateInputsMethod = new \ReflectionMethod('Optimizely\Optimizely', 'validateDatafile');
diff --git a/tests/ProjectConfigTest.php b/tests/ProjectConfigTest.php
index b2f4cd89..377a49f2 100644
--- a/tests/ProjectConfigTest.php
+++ b/tests/ProjectConfigTest.php
@@ -32,6 +32,7 @@
 use Optimizely\ErrorHandler\NoOpErrorHandler;
 use Optimizely\Exceptions\InvalidAttributeException;
 use Optimizely\Exceptions\InvalidAudienceException;
+use Optimizely\Exceptions\InvalidDatafileVersionException;
 use Optimizely\Exceptions\InvalidEventException;
 use Optimizely\Exceptions\InvalidExperimentException;
 use Optimizely\Exceptions\InvalidFeatureFlagException;
@@ -140,7 +141,8 @@ public function testInit()
         $this->assertEquals(
             [
             'purchase' => $this->config->getEvent('purchase'),
-            'unlinked_event' => $this->config->getEvent('unlinked_event')
+            'unlinked_event' => $this->config->getEvent('unlinked_event'),
+            'multi_exp_event' => $this->config->getEvent('multi_exp_event')
             ],
             $eventKeyMap->getValue($this->config)
         );
@@ -327,6 +329,21 @@ public function testInit()
         $this->assertEquals($expectedVariation, $actualVariation);
     }
 
+    public function testExceptionThrownForUnsupportedVersion()
+    {
+        // Verify that an exception is thrown when given datafile version is unsupported //
+        $this->setExpectedException(
+            InvalidDatafileVersionException::class,
+            'This version of the PHP SDK does not support the given datafile version: 5.'
+        );
+
+        $this->config = new ProjectConfig(
+            UNSUPPORTED_DATAFILE,
+            $this->loggerMock,
+            $this->errorHandlerMock
+        );
+    }
+
     public function testVariationParsingWithoutFeatureEnabledProp()
     {
         $variables = [
diff --git a/tests/TestData.php b/tests/TestData.php
index 8ebabe60..da38fb69 100644
--- a/tests/TestData.php
+++ b/tests/TestData.php
@@ -483,6 +483,14 @@
       "experimentIds": [],
       "id": "7718020064",
       "key": "unlinked_event"
+    },
+    {
+      "experimentIds":[
+        "7716830082",
+        "122230"
+      ],
+      "id": "7718020065",
+      "key": "multi_exp_event"
     }
   ],
   "anonymizeIP": false,
@@ -765,6 +773,60 @@
 }'
 );
 
+define(
+    'UNSUPPORTED_DATAFILE',
+    '{
+      "version": "5",
+      "rollouts": [],
+      "anonymizeIP": true,
+      "projectId": "10431130345",
+      "variables": [],
+      "featureFlags": [],
+      "experiments": [
+        {
+          "status": "Running",
+          "key": "ab_running_exp_untargeted",
+          "layerId": "10417730432",
+          "trafficAllocation": [
+            {
+              "entityId": "10418551353",
+              "endOfRange": 10000
+            }
+          ],
+          "audienceIds": [],
+          "variations": [
+            {
+              "variables": [],
+              "id": "10418551353",
+              "key": "all_traffic_variation"
+            },
+            {
+              "variables": [],
+              "id": "10418510624",
+              "key": "no_traffic_variation"
+            }
+          ],
+          "forcedVariations": {},
+          "id": "10420810910"
+        }
+      ],
+      "audiences": [],
+      "groups": [],
+      "attributes": [],
+      "accountId": "10367498574",
+      "events": [
+        {
+          "experimentIds": [
+            "10420810910"
+          ],
+          "id": "10404198134",
+          "key": "winning"
+        }
+      ],
+      "revision": "1337"
+    }'
+);
+
 /**
  * Class TestBucketer
  * Extending Bucketer for the sake of tests.