diff --git a/packages/optimizely-sdk/lib/core/event_builder/event_helpers.js b/packages/optimizely-sdk/lib/core/event_builder/event_helpers.js
index b35ccf672..aeeb958b2 100644
--- a/packages/optimizely-sdk/lib/core/event_builder/event_helpers.js
+++ b/packages/optimizely-sdk/lib/core/event_builder/event_helpers.js
@@ -140,7 +140,8 @@ exports.buildConversionEvent = function buildConversionEvent(config) {
 function buildVisitorAttributes(configObj, attributes) {
   var builtAttributes = [];
   // Omit attribute values that are not supported by the log endpoint.
-  fns.forOwn(attributes, function(attributeValue, attributeKey) {
+  Object.keys(attributes || {}).forEach(function(attributeKey) {
+    var attributeValue = attributes[attributeKey];
     if (attributesValidator.isAttributeValid(attributeKey, attributeValue)) {
       var attributeId = projectConfig.getAttributeId(configObj, attributeKey, logger);
       if (attributeId) {
diff --git a/packages/optimizely-sdk/lib/core/event_builder/index.js b/packages/optimizely-sdk/lib/core/event_builder/index.js
index cc977d3e7..ca27a7f29 100644
--- a/packages/optimizely-sdk/lib/core/event_builder/index.js
+++ b/packages/optimizely-sdk/lib/core/event_builder/index.js
@@ -61,7 +61,8 @@ function getCommonEventParams(options) {
   };
 
   // Omit attribute values that are not supported by the log endpoint.
-  fns.forOwn(attributes, function(attributeValue, attributeKey) {
+  Object.keys(attributes || {}).forEach(function(attributeKey) {
+    var attributeValue = attributes[attributeKey];
     if (attributeValidator.isAttributeValid(attributeKey, attributeValue)) {
       var attributeId = projectConfig.getAttributeId(options.configObj, attributeKey, options.logger);
       if (attributeId) {
diff --git a/packages/optimizely-sdk/lib/core/notification_center/index.js b/packages/optimizely-sdk/lib/core/notification_center/index.js
index 1bd334a50..42f5b86d5 100644
--- a/packages/optimizely-sdk/lib/core/notification_center/index.js
+++ b/packages/optimizely-sdk/lib/core/notification_center/index.js
@@ -15,7 +15,6 @@
  */
 
 var enums = require('../../utils/enums');
-var fns = require('../../utils/fns');
 var jsSdkUtils = require('@optimizely/js-sdk-utils');
 
 var LOG_LEVEL = enums.LOG_LEVEL;
@@ -37,7 +36,8 @@ function NotificationCenter(options) {
   this.logger = options.logger;
   this.errorHandler = options.errorHandler;
   this.__notificationListeners = {};
-  fns.forOwn(enums.NOTIFICATION_TYPES, function(notificationTypeEnum) {
+
+  jsSdkUtils.objectValues(enums.NOTIFICATION_TYPES).forEach(function(notificationTypeEnum) {
     this.__notificationListeners[notificationTypeEnum] = [];
   }.bind(this));
   this.__listenerId = 1;
@@ -101,7 +101,9 @@ NotificationCenter.prototype.removeNotificationListener = function (listenerId)
   try {
     var indexToRemove;
     var typeToRemove;
-    fns.forOwn(this.__notificationListeners, function (listenersForType, notificationType) {
+    
+    Object.keys(this.__notificationListeners).some(function(notificationType) {
+      var listenersForType = this.__notificationListeners[notificationType];
       (listenersForType || []).every(function(listenerEntry, i) {
         if (listenerEntry.id === listenerId) {
           indexToRemove = i;
@@ -111,10 +113,10 @@ NotificationCenter.prototype.removeNotificationListener = function (listenerId)
         return true
       });
       if (indexToRemove !== undefined && typeToRemove !== undefined) {
-        return false;
+        return true;
       }
-    });
-
+    }.bind(this));
+    
     if (indexToRemove !== undefined && typeToRemove !== undefined) {
       this.__notificationListeners[typeToRemove].splice(indexToRemove, 1);
       return true;
@@ -131,7 +133,7 @@ NotificationCenter.prototype.removeNotificationListener = function (listenerId)
  */
 NotificationCenter.prototype.clearAllNotificationListeners = function () {
   try{
-    fns.forOwn(enums.NOTIFICATION_TYPES, function (notificationTypeEnum) {
+    jsSdkUtils.objectValues(enums.NOTIFICATION_TYPES).forEach(function (notificationTypeEnum) {
       this.__notificationListeners[notificationTypeEnum] = [];
     }.bind(this));
   } catch (e) {
diff --git a/packages/optimizely-sdk/lib/core/project_config/index.js b/packages/optimizely-sdk/lib/core/project_config/index.js
index 7629e4553..29788e25b 100644
--- a/packages/optimizely-sdk/lib/core/project_config/index.js
+++ b/packages/optimizely-sdk/lib/core/project_config/index.js
@@ -15,7 +15,7 @@
  */
 var fns = require('../../utils/fns');
 var enums = require('../../utils/enums');
-var sprintf = require('@optimizely/js-sdk-utils').sprintf;
+var jsSdkUtils = require('@optimizely/js-sdk-utils');
 var configValidator = require('../../utils/config_validator');
 var projectConfigSchema = require('./project_config_schema');
 
@@ -60,7 +60,7 @@ module.exports = {
     });
 
     projectConfig.rolloutIdMap = fns.keyBy(projectConfig.rollouts || [], 'id');
-    fns.forOwn(projectConfig.rolloutIdMap, function(rollout) {
+    jsSdkUtils.objectValues(projectConfig.rolloutIdMap || {}).forEach(function (rollout) {      
       (rollout.experiments || []).forEach(function(experiment) {
         projectConfig.experiments.push(fns.cloneDeep(experiment));
         // Creates { <variationKey>: <variation> } map inside of the experiment
@@ -79,8 +79,7 @@ module.exports = {
 
       // Creates { <variationId>: { key: <variationKey>, id: <variationId> } } mapping for quick lookup
       fns.assign(projectConfig.variationIdMap, fns.keyBy(experiment.variations, 'id'));
-
-      fns.forOwn(experiment.variationKeyMap, function(variation) {
+      jsSdkUtils.objectValues(experiment.variationKeyMap || {}).forEach(function (variation) {
         if (variation.variables) {
           projectConfig.variationVariableUsageMap[variation.id] = fns.keyBy(variation.variables, 'id');
         }
@@ -92,7 +91,7 @@ module.exports = {
     projectConfig.experimentFeatureMap = {};
 
     projectConfig.featureKeyMap = fns.keyBy(projectConfig.featureFlags || [], 'key');
-    fns.forOwn(projectConfig.featureKeyMap, function(feature) {
+    jsSdkUtils.objectValues(projectConfig.featureKeyMap || {}).forEach(function (feature) {
       feature.variableKeyMap = fns.keyBy(feature.variables, 'key');
       (feature.experimentIds || []).forEach(function(experimentId) {
         // Add this experiment in experiment-feature map.
@@ -123,7 +122,7 @@ module.exports = {
   getExperimentId: function(projectConfig, experimentKey) {
     var experiment = projectConfig.experimentKeyMap[experimentKey];
     if (!experiment) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
     }
     return experiment.id;
   },
@@ -138,7 +137,7 @@ module.exports = {
   getLayerId: function(projectConfig, experimentId) {
     var experiment = projectConfig.experimentIdMap[experimentId];
     if (!experiment) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_ID, MODULE_NAME, experimentId));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_ID, MODULE_NAME, experimentId));
     }
     return experiment.layerId;
   },
@@ -156,14 +155,14 @@ module.exports = {
     if (attribute) {
       if (hasReservedPrefix) {
         logger.log(LOG_LEVEL.WARN,
-                   sprintf('Attribute %s unexpectedly has reserved prefix %s; using attribute ID instead of reserved attribute name.', attributeKey, RESERVED_ATTRIBUTE_PREFIX));
+                   jsSdkUtils.sprintf('Attribute %s unexpectedly has reserved prefix %s; using attribute ID instead of reserved attribute name.', attributeKey, RESERVED_ATTRIBUTE_PREFIX));
       }
       return attribute.id;
     } else if (hasReservedPrefix) {
       return attributeKey;
     }
 
-    logger.log(LOG_LEVEL.DEBUG, sprintf(ERROR_MESSAGES.UNRECOGNIZED_ATTRIBUTE, MODULE_NAME, attributeKey));
+    logger.log(LOG_LEVEL.DEBUG, jsSdkUtils.sprintf(ERROR_MESSAGES.UNRECOGNIZED_ATTRIBUTE, MODULE_NAME, attributeKey));
     return null;
   },
 
@@ -191,7 +190,7 @@ module.exports = {
   getExperimentStatus: function(projectConfig, experimentKey) {
     var experiment = projectConfig.experimentKeyMap[experimentKey];
     if (!experiment) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
     }
     return experiment.status;
   },
@@ -225,7 +224,7 @@ module.exports = {
   getExperimentAudienceConditions: function(projectConfig, experimentKey) {
     var experiment = projectConfig.experimentKeyMap[experimentKey];
     if (!experiment) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
     }
 
     return experiment.audienceConditions || experiment.audienceIds;
@@ -274,7 +273,7 @@ module.exports = {
       }
     }
 
-    throw new Error(sprintf(ERROR_MESSAGES.EXPERIMENT_KEY_NOT_IN_DATAFILE, MODULE_NAME, experimentKey));
+    throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.EXPERIMENT_KEY_NOT_IN_DATAFILE, MODULE_NAME, experimentKey));
   },
 
   /**
@@ -287,7 +286,7 @@ module.exports = {
   getTrafficAllocation: function(projectConfig, experimentKey) {
     var experiment = projectConfig.experimentKeyMap[experimentKey];
     if (!experiment) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
     }
     return experiment.trafficAllocation;
   },
@@ -307,7 +306,7 @@ module.exports = {
       }
     }
 
-    logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_ID, MODULE_NAME, experimentId));
+    logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_ID, MODULE_NAME, experimentId));
     return null;
   },
 
@@ -328,7 +327,7 @@ module.exports = {
       }
     }
 
-    logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.FEATURE_NOT_IN_DATAFILE, MODULE_NAME, featureKey));
+    logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.FEATURE_NOT_IN_DATAFILE, MODULE_NAME, featureKey));
     return null;
   },
 
@@ -346,13 +345,13 @@ module.exports = {
   getVariableForFeature: function(projectConfig, featureKey, variableKey, logger) {
     var feature = projectConfig.featureKeyMap[featureKey];
     if (!feature) {
-      logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.FEATURE_NOT_IN_DATAFILE, MODULE_NAME, featureKey));
+      logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.FEATURE_NOT_IN_DATAFILE, MODULE_NAME, featureKey));
       return null;
     }
 
     var variable = feature.variableKeyMap[variableKey];
     if (!variable) {
-      logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.VARIABLE_KEY_NOT_IN_DATAFILE, MODULE_NAME, variableKey, featureKey));
+      logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.VARIABLE_KEY_NOT_IN_DATAFILE, MODULE_NAME, variableKey, featureKey));
       return null;
     }
 
@@ -377,7 +376,7 @@ module.exports = {
     }
 
     if (!projectConfig.variationVariableUsageMap.hasOwnProperty(variation.id)) {
-      logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.VARIATION_ID_NOT_IN_DATAFILE_NO_EXPERIMENT, MODULE_NAME, variation.id));
+      logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.VARIATION_ID_NOT_IN_DATAFILE_NO_EXPERIMENT, MODULE_NAME, variation.id));
       return null;
     }
 
@@ -409,7 +408,7 @@ module.exports = {
     switch (variableType) {
       case FEATURE_VARIABLE_TYPES.BOOLEAN:
         if (variableValue !== 'true' && variableValue !== 'false') {
-          logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
+          logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
           castValue = null;
         } else {
           castValue = variableValue === 'true';
@@ -419,7 +418,7 @@ module.exports = {
       case FEATURE_VARIABLE_TYPES.INTEGER:
         castValue = parseInt(variableValue, 10);
         if (isNaN(castValue)) {
-          logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
+          logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
           castValue = null;
         }
         break;
@@ -427,7 +426,7 @@ module.exports = {
       case FEATURE_VARIABLE_TYPES.DOUBLE:
         castValue = parseFloat(variableValue);
         if (isNaN(castValue)) {
-          logger.log(LOG_LEVEL.ERROR, sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
+          logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(ERROR_MESSAGES.UNABLE_TO_CAST_VALUE, MODULE_NAME, variableValue, variableType));
           castValue = null;
         }
         break;
@@ -485,10 +484,10 @@ module.exports = {
   tryCreatingProjectConfig: function(config) {
     configValidator.validateDatafile(config.datafile);
     if (config.skipJSONValidation === true) {
-      config.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.SKIPPING_JSON_VALIDATION, MODULE_NAME));
+      config.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.SKIPPING_JSON_VALIDATION, MODULE_NAME));
     } else if (config.jsonSchemaValidator) {
       config.jsonSchemaValidator.validate(projectConfigSchema, config.datafile);
-      config.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.VALID_DATAFILE, MODULE_NAME));
+      config.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.VALID_DATAFILE, MODULE_NAME));
     }
     return module.exports.createProjectConfig(config.datafile);
   },
diff --git a/packages/optimizely-sdk/lib/optimizely/index.js b/packages/optimizely-sdk/lib/optimizely/index.js
index 610297a87..762e997e8 100644
--- a/packages/optimizely-sdk/lib/optimizely/index.js
+++ b/packages/optimizely-sdk/lib/optimizely/index.js
@@ -24,7 +24,7 @@ var eventProcessor = require('@optimizely/js-sdk-event-processor');
 var eventTagsValidator = require('../utils/event_tags_validator');
 var notificationCenter = require('../core/notification_center');
 var projectConfig = require('../core/project_config');
-var sprintf = require('@optimizely/js-sdk-utils').sprintf;
+var jsSdkUtils = require('@optimizely/js-sdk-utils');
 var userProfileServiceValidator = require('../utils/user_profile_service_validator');
 var stringValidator = require('../utils/string_value_validator');
 var projectConfigManager = require('../core/project_config/project_config_manager');
@@ -57,7 +57,7 @@ var DEFAULT_ONREADY_TIMEOUT = 30000;
 function Optimizely(config) {
   var clientEngine = config.clientEngine;
   if (enums.VALID_CLIENT_ENGINES.indexOf(clientEngine) === -1) {
-    config.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.INVALID_CLIENT_ENGINE, MODULE_NAME, clientEngine));
+    config.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_CLIENT_ENGINE, MODULE_NAME, clientEngine));
     clientEngine = enums.NODE_CLIENT_ENGINE;
   }
 
@@ -77,7 +77,7 @@ function Optimizely(config) {
   });
 
   this.__disposeOnUpdate = this.projectConfigManager.onUpdate(function(configObj) {
-    this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.UPDATED_OPTIMIZELY_CONFIG, MODULE_NAME, configObj.revision, configObj.projectId));
+    this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.UPDATED_OPTIMIZELY_CONFIG, MODULE_NAME, configObj.revision, configObj.projectId));
     this.notificationCenter.sendNotifications(NOTIFICATION_TYPES.OPTIMIZELY_CONFIG_UPDATE);
   }.bind(this));
 
@@ -88,7 +88,7 @@ function Optimizely(config) {
     try {
       if (userProfileServiceValidator.validate(config.userProfileService)) {
         userProfileService = config.userProfileService;
-        this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.VALID_USER_PROFILE_SERVICE, MODULE_NAME));
+        this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.VALID_USER_PROFILE_SERVICE, MODULE_NAME));
       }
     } catch (ex) {
       this.logger.log(LOG_LEVEL.WARNING, ex.message);
@@ -138,7 +138,7 @@ Optimizely.prototype.__isValidInstance = function() {
 Optimizely.prototype.activate = function(experimentKey, userId, attributes) {
   try {
     if (!this.__isValidInstance()) {
-      this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'activate'));
+      this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'activate'));
       return null;
     }
 
@@ -159,7 +159,7 @@ Optimizely.prototype.activate = function(experimentKey, userId, attributes) {
 
       // If experiment is not set to 'Running' status, log accordingly and return variation key
       if (!projectConfig.isRunning(configObj, experimentKey)) {
-        var shouldNotDispatchActivateLogMessage = sprintf(
+        var shouldNotDispatchActivateLogMessage = jsSdkUtils.sprintf(
           LOG_MESSAGES.SHOULD_NOT_DISPATCH_ACTIVATE,
           MODULE_NAME,
           experimentKey
@@ -173,7 +173,7 @@ Optimizely.prototype.activate = function(experimentKey, userId, attributes) {
       return variationKey;
     } catch (ex) {
       this.logger.log(LOG_LEVEL.ERROR, ex.message);
-      var failedActivationLogMessage = sprintf(LOG_MESSAGES.NOT_ACTIVATING_USER, MODULE_NAME, userId, experimentKey);
+      var failedActivationLogMessage = jsSdkUtils.sprintf(LOG_MESSAGES.NOT_ACTIVATING_USER, MODULE_NAME, userId, experimentKey);
       this.logger.log(LOG_LEVEL.INFO, failedActivationLogMessage);
       this.errorHandler.handleError(ex);
       return null;
@@ -271,7 +271,7 @@ Optimizely.prototype.__emitNotificationCenterActivate = function(experimentKey,
 Optimizely.prototype.track = function(eventKey, userId, attributes, eventTags) {
   try {
     if (!this.__isValidInstance()) {
-      this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'track'));
+      this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'track'));
       return;
     }
 
@@ -285,7 +285,7 @@ Optimizely.prototype.track = function(eventKey, userId, attributes, eventTags) {
     }
 
     if (!projectConfig.eventWithKeyExists(configObj, eventKey)) {
-      throw new Error(sprintf(ERROR_MESSAGES.INVALID_EVENT_KEY, MODULE_NAME, eventKey));
+      throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EVENT_KEY, MODULE_NAME, eventKey));
     }
 
     // remove null values from eventTags
@@ -299,14 +299,14 @@ Optimizely.prototype.track = function(eventKey, userId, attributes, eventTags) {
       clientVersion: this.clientVersion,
       configObj: configObj,
     });
-    this.logger.log(LOG_LEVEL.INFO, sprintf(enums.LOG_MESSAGES.TRACK_EVENT, MODULE_NAME, eventKey, userId));
+    this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(enums.LOG_MESSAGES.TRACK_EVENT, MODULE_NAME, eventKey, userId));
     // TODO is it okay to not pass a projectConfig as second argument
     this.eventProcessor.process(conversionEvent);
     this.__emitNotificationCenterTrack(eventKey, userId, attributes, eventTags);
   } catch (e) {
     this.logger.log(LOG_LEVEL.ERROR, e.message);
     this.errorHandler.handleError(e);
-    var failedTrackLogMessage = sprintf(LOG_MESSAGES.NOT_TRACKING_USER, MODULE_NAME, userId);
+    var failedTrackLogMessage = jsSdkUtils.sprintf(LOG_MESSAGES.NOT_TRACKING_USER, MODULE_NAME, userId);
     this.logger.log(LOG_LEVEL.INFO, failedTrackLogMessage);
   }
 };
@@ -360,7 +360,7 @@ Optimizely.prototype.__emitNotificationCenterTrack = function(eventKey, userId,
 Optimizely.prototype.getVariation = function(experimentKey, userId, attributes) {
   try {
     if (!this.__isValidInstance()) {
-      this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'getVariation'));
+      this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'getVariation'));
       return null;
     }
 
@@ -376,7 +376,7 @@ Optimizely.prototype.getVariation = function(experimentKey, userId, attributes)
 
       var experiment = configObj.experimentKeyMap[experimentKey];
       if (!experiment) {
-        this.logger.log(LOG_LEVEL.DEBUG, sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
+        this.logger.log(LOG_LEVEL.DEBUG, jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_EXPERIMENT_KEY, MODULE_NAME, experimentKey));
         return null;
       }
 
@@ -475,7 +475,7 @@ Optimizely.prototype.__validateInputs = function(stringInputs, userAttributes, e
     if (stringInputs.hasOwnProperty('user_id')) {
       var userId = stringInputs.user_id;
       if (typeof userId !== 'string' || userId === null || userId === 'undefined') {
-        throw new Error(sprintf(ERROR_MESSAGES.INVALID_INPUT_FORMAT, MODULE_NAME, 'user_id'));
+        throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_INPUT_FORMAT, MODULE_NAME, 'user_id'));
       }
 
       delete stringInputs.user_id;
@@ -485,7 +485,7 @@ Optimizely.prototype.__validateInputs = function(stringInputs, userAttributes, e
     for (var index = 0; index < inputKeys.length; index++) {
       var key = inputKeys[index];
       if (!stringValidator.validate(stringInputs[key])) {
-        throw new Error(sprintf(ERROR_MESSAGES.INVALID_INPUT_FORMAT, MODULE_NAME, key));
+        throw new Error(jsSdkUtils.sprintf(ERROR_MESSAGES.INVALID_INPUT_FORMAT, MODULE_NAME, key));
       }
     }
     if (userAttributes) {
@@ -509,7 +509,7 @@ Optimizely.prototype.__validateInputs = function(stringInputs, userAttributes, e
  * @return {null}
  */
 Optimizely.prototype.__notActivatingExperiment = function(experimentKey, userId) {
-  var failedActivationLogMessage = sprintf(LOG_MESSAGES.NOT_ACTIVATING_USER, MODULE_NAME, userId, experimentKey);
+  var failedActivationLogMessage = jsSdkUtils.sprintf(LOG_MESSAGES.NOT_ACTIVATING_USER, MODULE_NAME, userId, experimentKey);
   this.logger.log(LOG_LEVEL.INFO, failedActivationLogMessage);
   return null;
 };
@@ -538,7 +538,7 @@ Optimizely.prototype.__filterEmptyValues = function(map) {
 Optimizely.prototype.isFeatureEnabled = function(featureKey, userId, attributes) {
   try {
     if (!this.__isValidInstance()) {
-      this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'isFeatureEnabled'));
+      this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'isFeatureEnabled'));
       return false;
     }
 
@@ -574,9 +574,9 @@ Optimizely.prototype.isFeatureEnabled = function(featureKey, userId, attributes)
     }
 
     if (featureEnabled === true) {
-      this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.FEATURE_ENABLED_FOR_USER, MODULE_NAME, featureKey, userId));
+      this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.FEATURE_ENABLED_FOR_USER, MODULE_NAME, featureKey, userId));
     } else {
-      this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.FEATURE_NOT_ENABLED_FOR_USER, MODULE_NAME, featureKey, userId));
+      this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.FEATURE_NOT_ENABLED_FOR_USER, MODULE_NAME, featureKey, userId));
       featureEnabled = false;
     }
 
@@ -616,7 +616,7 @@ Optimizely.prototype.getEnabledFeatures = function(userId, attributes) {
   try {
     var enabledFeatures = [];
     if (!this.__isValidInstance()) {
-      this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'getEnabledFeatures'));
+      this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, 'getEnabledFeatures'));
       return enabledFeatures;
     }
 
@@ -629,14 +629,11 @@ Optimizely.prototype.getEnabledFeatures = function(userId, attributes) {
       return enabledFeatures;
     }
 
-    fns.forOwn(
-      configObj.featureKeyMap,
-      function(feature) {
-        if (this.isFeatureEnabled(feature.key, userId, attributes)) {
-          enabledFeatures.push(feature.key);
-        }
-      }.bind(this)
-    );
+    jsSdkUtils.objectValues(configObj.featureKeyMap).forEach(function (feature) {
+      if (this.isFeatureEnabled(feature.key, userId, attributes)) {
+        enabledFeatures.push(feature.key);
+      }
+    }.bind(this));
 
     return enabledFeatures;
   } catch (e) {
@@ -696,7 +693,7 @@ Optimizely.prototype.getFeatureVariable = function(featureKey, variableKey, user
 Optimizely.prototype._getFeatureVariableForType = function(featureKey, variableKey, variableType, userId, attributes) {
   if (!this.__isValidInstance()) {
     var apiName = (variableType) ? 'getFeatureVariable' + variableType.charAt(0).toUpperCase() + variableType.slice(1) : 'getFeatureVariable';
-    this.logger.log(LOG_LEVEL.ERROR, sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, apiName));
+    this.logger.log(LOG_LEVEL.ERROR, jsSdkUtils.sprintf(LOG_MESSAGES.INVALID_OBJECT, MODULE_NAME, apiName));
     return null;
   }
 
@@ -724,7 +721,7 @@ Optimizely.prototype._getFeatureVariableForType = function(featureKey, variableK
   } else if (variable.type !== variableType) {
     this.logger.log(
       LOG_LEVEL.WARNING,
-      sprintf(LOG_MESSAGES.VARIABLE_REQUESTED_WITH_WRONG_TYPE, MODULE_NAME, variableType, variable.type)
+      jsSdkUtils.sprintf(LOG_MESSAGES.VARIABLE_REQUESTED_WITH_WRONG_TYPE, MODULE_NAME, variableType, variable.type)
     );
     return null;
   }
@@ -739,16 +736,16 @@ Optimizely.prototype._getFeatureVariableForType = function(featureKey, variableK
     if (value !== null) {
       if (featureEnabled === true) {
         variableValue = value;
-        this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_VARIABLE_VALUE, MODULE_NAME, variableKey, featureFlag.key, variableValue, userId));
+        this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.USER_RECEIVED_VARIABLE_VALUE, MODULE_NAME, variableKey, featureFlag.key, variableValue, userId));
       } else {
-        this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.FEATURE_NOT_ENABLED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME,
+        this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.FEATURE_NOT_ENABLED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME,
           featureFlag.key, userId, variableKey));
       }
     } else {
-      this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.VARIABLE_NOT_USED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME, variableKey, decision.variation.key));
+      this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.VARIABLE_NOT_USED_RETURN_DEFAULT_VARIABLE_VALUE, MODULE_NAME, variableKey, decision.variation.key));
     }
   } else {
-    this.logger.log(LOG_LEVEL.INFO, sprintf(LOG_MESSAGES.USER_RECEIVED_DEFAULT_VARIABLE_VALUE, MODULE_NAME, userId,
+    this.logger.log(LOG_LEVEL.INFO, jsSdkUtils.sprintf(LOG_MESSAGES.USER_RECEIVED_DEFAULT_VARIABLE_VALUE, MODULE_NAME, userId,
       variableKey, featureFlag.key));
   }
 
@@ -1045,7 +1042,7 @@ Optimizely.prototype.onReady = function(options) {
     delete this.__readyTimeouts[timeoutId];
     resolveTimeoutPromise({
       success: false,
-      reason: sprintf('onReady timeout expired after %s ms', timeout),
+      reason: jsSdkUtils.sprintf('onReady timeout expired after %s ms', timeout),
     });
   }.bind(this);
   var readyTimeout = setTimeout(onReadyTimeout, timeout);
diff --git a/packages/optimizely-sdk/lib/utils/attributes_validator/index.tests.js b/packages/optimizely-sdk/lib/utils/attributes_validator/index.tests.js
index 8703511c6..4e0c672ab 100644
--- a/packages/optimizely-sdk/lib/utils/attributes_validator/index.tests.js
+++ b/packages/optimizely-sdk/lib/utils/attributes_validator/index.tests.js
@@ -72,7 +72,8 @@ describe('lib/utils/attributes_validator', function() {
           '': 'javascript',
         };
 
-        fns.forOwn(userAttributes, function(value, key) {
+        Object.keys(userAttributes).forEach(function (key) {
+          var value = userAttributes[key];  
           assert.isTrue(attributesValidator.isAttributeValid(key, value));
         });
       });
@@ -88,7 +89,8 @@ describe('lib/utils/attributes_validator', function() {
           'outOfBound': Math.pow(2, 53) + 2,
         };
 
-        fns.forOwn(userAttributes, function(value, key) {
+        Object.keys(userAttributes).forEach(function (key) {
+          var value = userAttributes[key];
           assert.isFalse(attributesValidator.isAttributeValid(key, value));
         });
       });
diff --git a/packages/optimizely-sdk/lib/utils/fns/index.js b/packages/optimizely-sdk/lib/utils/fns/index.js
index 4895106a3..6c99c7d9f 100644
--- a/packages/optimizely-sdk/lib/utils/fns/index.js
+++ b/packages/optimizely-sdk/lib/utils/fns/index.js
@@ -54,7 +54,6 @@ module.exports = {
       return item[key];
     });
   },
-  forOwn: require('lodash/forOwn'),
   uuid: function() {
     return uuid.v4();
   },