diff --git a/apps/advanced/common/models/User.php b/apps/advanced/common/models/User.php
index df1d6b0..dd67959 100644
--- a/apps/advanced/common/models/User.php
+++ b/apps/advanced/common/models/User.php
@@ -2,7 +2,7 @@
 namespace common\models;
 
 use yii\db\ActiveRecord;
-use yii\helpers\SecurityHelper;
+use yii\helpers\Security;
 use yii\web\Identity;
 
 /**
@@ -72,7 +72,7 @@ class User extends ActiveRecord implements Identity
 
 	public function validatePassword($password)
 	{
-		return SecurityHelper::validatePassword($password, $this->password_hash);
+		return Security::validatePassword($password, $this->password_hash);
 	}
 
 	public function rules()
@@ -105,10 +105,10 @@ class User extends ActiveRecord implements Identity
 	{
 		if (parent::beforeSave($insert)) {
 			if (($this->isNewRecord || $this->getScenario() === 'resetPassword') && !empty($this->password)) {
-				$this->password_hash = SecurityHelper::generatePasswordHash($this->password);
+				$this->password_hash = Security::generatePasswordHash($this->password);
 			}
 			if ($this->isNewRecord) {
-				$this->auth_key = SecurityHelper::generateRandomKey();
+				$this->auth_key = Security::generateRandomKey();
 			}
 			return true;
 		}
diff --git a/apps/advanced/frontend/models/SendPasswordResetTokenForm.php b/apps/advanced/frontend/models/SendPasswordResetTokenForm.php
index 05c8f99..5e48084 100644
--- a/apps/advanced/frontend/models/SendPasswordResetTokenForm.php
+++ b/apps/advanced/frontend/models/SendPasswordResetTokenForm.php
@@ -4,7 +4,7 @@ namespace frontend\models;
 use yii\base\Model;
 use common\models\User;
 use yii\base\View;
-use yii\helpers\SecurityHelper;
+use yii\helpers\Security;
 
 /**
  * SendPasswordResetTokenForm is the model behind requesting password reset token form.
@@ -33,7 +33,7 @@ class SendPasswordResetTokenForm extends Model
 				'status' => User::STATUS_ACTIVE,
 			));
 			if ($user) {
-				$user->password_reset_token = SecurityHelper::generateRandomKey();
+				$user->password_reset_token = Security::generateRandomKey();
 				if ($user->save(false)) {
 					$view = new View(array(
 						'context' => \Yii::$app->controller,
diff --git a/framework/yii/classes.php b/framework/yii/classes.php
index 5cd6e3b..41c9a3a 100644
--- a/framework/yii/classes.php
+++ b/framework/yii/classes.php
@@ -46,19 +46,34 @@ return array(
 	'yii\base\ViewRenderer' => YII_PATH . '/base/ViewRenderer.php',
 	'yii\base\Widget' => YII_PATH . '/base/Widget.php',
 	'yii\behaviors\AutoTimestamp' => YII_PATH . '/behaviors/AutoTimestamp.php',
+	'yii\bootstrap\AffixAsset' => YII_PATH . '/bootstrap/AffixAsset.php',
 	'yii\bootstrap\Alert' => YII_PATH . '/bootstrap/Alert.php',
+	'yii\bootstrap\AlertAsset' => YII_PATH . '/bootstrap/AlertAsset.php',
+	'yii\bootstrap\BootstrapAsset' => YII_PATH . '/bootstrap/BootstrapAsset.php',
 	'yii\bootstrap\Button' => YII_PATH . '/bootstrap/Button.php',
+	'yii\bootstrap\ButtonAsset' => YII_PATH . '/bootstrap/ButtonAsset.php',
 	'yii\bootstrap\ButtonDropdown' => YII_PATH . '/bootstrap/ButtonDropdown.php',
 	'yii\bootstrap\ButtonGroup' => YII_PATH . '/bootstrap/ButtonGroup.php',
 	'yii\bootstrap\Carousel' => YII_PATH . '/bootstrap/Carousel.php',
+	'yii\bootstrap\CarouselAsset' => YII_PATH . '/bootstrap/CarouselAsset.php',
 	'yii\bootstrap\Collapse' => YII_PATH . '/bootstrap/Collapse.php',
+	'yii\bootstrap\CollapseAsset' => YII_PATH . '/bootstrap/CollapseAsset.php',
 	'yii\bootstrap\Dropdown' => YII_PATH . '/bootstrap/Dropdown.php',
+	'yii\bootstrap\DropdownAsset' => YII_PATH . '/bootstrap/DropdownAsset.php',
 	'yii\bootstrap\Modal' => YII_PATH . '/bootstrap/Modal.php',
+	'yii\bootstrap\ModalAsset' => YII_PATH . '/bootstrap/ModalAsset.php',
 	'yii\bootstrap\Nav' => YII_PATH . '/bootstrap/Nav.php',
 	'yii\bootstrap\NavBar' => YII_PATH . '/bootstrap/NavBar.php',
+	'yii\bootstrap\PopoverAsset' => YII_PATH . '/bootstrap/PopoverAsset.php',
 	'yii\bootstrap\Progress' => YII_PATH . '/bootstrap/Progress.php',
+	'yii\bootstrap\ResponsiveAsset' => YII_PATH . '/bootstrap/ResponsiveAsset.php',
+	'yii\bootstrap\ScrollspyAsset' => YII_PATH . '/bootstrap/ScrollspyAsset.php',
+	'yii\bootstrap\TabAsset' => YII_PATH . '/bootstrap/TabAsset.php',
 	'yii\bootstrap\Tabs' => YII_PATH . '/bootstrap/Tabs.php',
-	'yii\bootstrap\TypeAhead' => YII_PATH . '/bootstrap/TypeAhead.php',
+	'yii\bootstrap\TooltipAsset' => YII_PATH . '/bootstrap/TooltipAsset.php',
+	'yii\bootstrap\TransitionAsset' => YII_PATH . '/bootstrap/TransitionAsset.php',
+	'yii\bootstrap\Typeahead' => YII_PATH . '/bootstrap/Typeahead.php',
+	'yii\bootstrap\TypeaheadAsset' => YII_PATH . '/bootstrap/TypeaheadAsset.php',
 	'yii\bootstrap\Widget' => YII_PATH . '/bootstrap/Widget.php',
 	'yii\caching\ApcCache' => YII_PATH . '/caching/ApcCache.php',
 	'yii\caching\Cache' => YII_PATH . '/caching/Cache.php',
@@ -109,27 +124,27 @@ return array(
 	'yii\db\TableSchema' => YII_PATH . '/db/TableSchema.php',
 	'yii\db\Transaction' => YII_PATH . '/db/Transaction.php',
 	'yii\helpers\ArrayHelper' => YII_PATH . '/helpers/ArrayHelper.php',
-	'yii\helpers\base\ArrayHelper' => YII_PATH . '/helpers/base/ArrayHelper.php',
-	'yii\helpers\base\Console' => YII_PATH . '/helpers/base/Console.php',
-	'yii\helpers\base\FileHelper' => YII_PATH . '/helpers/base/FileHelper.php',
-	'yii\helpers\base\Html' => YII_PATH . '/helpers/base/Html.php',
-	'yii\helpers\base\HtmlPurifier' => YII_PATH . '/helpers/base/HtmlPurifier.php',
-	'yii\helpers\base\Inflector' => YII_PATH . '/helpers/base/Inflector.php',
-	'yii\helpers\base\Json' => YII_PATH . '/helpers/base/Json.php',
-	'yii\helpers\base\Markdown' => YII_PATH . '/helpers/base/Markdown.php',
-	'yii\helpers\base\SecurityHelper' => YII_PATH . '/helpers/base/SecurityHelper.php',
-	'yii\helpers\base\StringHelper' => YII_PATH . '/helpers/base/StringHelper.php',
-	'yii\helpers\base\VarDumper' => YII_PATH . '/helpers/base/VarDumper.php',
+	'yii\helpers\ArrayHelperBase' => YII_PATH . '/helpers/ArrayHelperBase.php',
 	'yii\helpers\Console' => YII_PATH . '/helpers/Console.php',
+	'yii\helpers\ConsoleBase' => YII_PATH . '/helpers/ConsoleBase.php',
 	'yii\helpers\FileHelper' => YII_PATH . '/helpers/FileHelper.php',
+	'yii\helpers\FileHelperBase' => YII_PATH . '/helpers/FileHelperBase.php',
 	'yii\helpers\Html' => YII_PATH . '/helpers/Html.php',
+	'yii\helpers\HtmlBase' => YII_PATH . '/helpers/HtmlBase.php',
 	'yii\helpers\HtmlPurifier' => YII_PATH . '/helpers/HtmlPurifier.php',
+	'yii\helpers\HtmlPurifierBase' => YII_PATH . '/helpers/HtmlPurifierBase.php',
 	'yii\helpers\Inflector' => YII_PATH . '/helpers/Inflector.php',
+	'yii\helpers\InflectorBase' => YII_PATH . '/helpers/InflectorBase.php',
 	'yii\helpers\Json' => YII_PATH . '/helpers/Json.php',
+	'yii\helpers\JsonBase' => YII_PATH . '/helpers/JsonBase.php',
 	'yii\helpers\Markdown' => YII_PATH . '/helpers/Markdown.php',
-	'yii\helpers\SecurityHelper' => YII_PATH . '/helpers/SecurityHelper.php',
+	'yii\helpers\MarkdownBase' => YII_PATH . '/helpers/MarkdownBase.php',
+	'yii\helpers\Security' => YII_PATH . '/helpers/Security.php',
+	'yii\helpers\SecurityBase' => YII_PATH . '/helpers/SecurityBase.php',
 	'yii\helpers\StringHelper' => YII_PATH . '/helpers/StringHelper.php',
+	'yii\helpers\StringHelperBase' => YII_PATH . '/helpers/StringHelperBase.php',
 	'yii\helpers\VarDumper' => YII_PATH . '/helpers/VarDumper.php',
+	'yii\helpers\VarDumperBase' => YII_PATH . '/helpers/VarDumperBase.php',
 	'yii\i18n\DbMessageSource' => YII_PATH . '/i18n/DbMessageSource.php',
 	'yii\i18n\Formatter' => YII_PATH . '/i18n/Formatter.php',
 	'yii\i18n\GettextFile' => YII_PATH . '/i18n/GettextFile.php',
@@ -162,12 +177,14 @@ return array(
 	'yii\validators\FilterValidator' => YII_PATH . '/validators/FilterValidator.php',
 	'yii\validators\InlineValidator' => YII_PATH . '/validators/InlineValidator.php',
 	'yii\validators\NumberValidator' => YII_PATH . '/validators/NumberValidator.php',
+	'yii\validators\PunycodeAsset' => YII_PATH . '/validators/PunycodeAsset.php',
 	'yii\validators\RangeValidator' => YII_PATH . '/validators/RangeValidator.php',
 	'yii\validators\RegularExpressionValidator' => YII_PATH . '/validators/RegularExpressionValidator.php',
 	'yii\validators\RequiredValidator' => YII_PATH . '/validators/RequiredValidator.php',
 	'yii\validators\StringValidator' => YII_PATH . '/validators/StringValidator.php',
 	'yii\validators\UniqueValidator' => YII_PATH . '/validators/UniqueValidator.php',
 	'yii\validators\UrlValidator' => YII_PATH . '/validators/UrlValidator.php',
+	'yii\validators\ValidationAsset' => YII_PATH . '/validators/ValidationAsset.php',
 	'yii\validators\Validator' => YII_PATH . '/validators/Validator.php',
 	'yii\web\AccessControl' => YII_PATH . '/web/AccessControl.php',
 	'yii\web\AccessRule' => YII_PATH . '/web/AccessRule.php',
@@ -186,6 +203,7 @@ return array(
 	'yii\web\HttpException' => YII_PATH . '/web/HttpException.php',
 	'yii\web\IAssetConverter' => YII_PATH . '/web/IAssetConverter.php',
 	'yii\web\Identity' => YII_PATH . '/web/Identity.php',
+	'yii\web\JqueryAsset' => YII_PATH . '/web/JqueryAsset.php',
 	'yii\web\JsExpression' => YII_PATH . '/web/JsExpression.php',
 	'yii\web\PageCache' => YII_PATH . '/web/PageCache.php',
 	'yii\web\Request' => YII_PATH . '/web/Request.php',
@@ -201,20 +219,22 @@ return array(
 	'yii\web\UserEvent' => YII_PATH . '/web/UserEvent.php',
 	'yii\web\VerbFilter' => YII_PATH . '/web/VerbFilter.php',
 	'yii\web\XmlResponseFormatter' => YII_PATH . '/web/XmlResponseFormatter.php',
+	'yii\web\YiiAsset' => YII_PATH . '/web/YiiAsset.php',
 	'yii\widgets\ActiveField' => YII_PATH . '/widgets/ActiveField.php',
 	'yii\widgets\ActiveForm' => YII_PATH . '/widgets/ActiveForm.php',
-	'yii\widgets\BaseListView' => YII_PATH . '/widgets/BaseListView.php',
+	'yii\widgets\ActiveFormAsset' => YII_PATH . '/widgets/ActiveFormAsset.php',
 	'yii\widgets\Block' => YII_PATH . '/widgets/Block.php',
 	'yii\widgets\Breadcrumbs' => YII_PATH . '/widgets/Breadcrumbs.php',
 	'yii\widgets\Captcha' => YII_PATH . '/widgets/Captcha.php',
+	'yii\widgets\CaptchaAsset' => YII_PATH . '/widgets/CaptchaAsset.php',
 	'yii\widgets\ContentDecorator' => YII_PATH . '/widgets/ContentDecorator.php',
 	'yii\widgets\DetailView' => YII_PATH . '/widgets/DetailView.php',
 	'yii\widgets\FragmentCache' => YII_PATH . '/widgets/FragmentCache.php',
 	'yii\widgets\InputWidget' => YII_PATH . '/widgets/InputWidget.php',
 	'yii\widgets\LinkPager' => YII_PATH . '/widgets/LinkPager.php',
 	'yii\widgets\ListPager' => YII_PATH . '/widgets/ListPager.php',
-	'yii\widgets\ListView' => YII_PATH . '/widgets/ListView.php',
 	'yii\widgets\MaskedInput' => YII_PATH . '/widgets/MaskedInput.php',
+	'yii\widgets\MaskedInputAsset' => YII_PATH . '/widgets/MaskedInputAsset.php',
 	'yii\widgets\Menu' => YII_PATH . '/widgets/Menu.php',
 	'yii\widgets\Spaceless' => YII_PATH . '/widgets/Spaceless.php',
 );
diff --git a/framework/yii/console/Controller.php b/framework/yii/console/Controller.php
index e4d4211..f605893 100644
--- a/framework/yii/console/Controller.php
+++ b/framework/yii/console/Controller.php
@@ -137,7 +137,7 @@ class Controller extends \yii\base\Controller
 	/**
 	 * Formats a string with ANSI codes
 	 *
-	 * You may pass additional parameters using the constants defined in [[yii\helpers\base\Console]].
+	 * You may pass additional parameters using the constants defined in [[yii\helpers\Console]].
 	 *
 	 * Example:
 	 *
@@ -162,7 +162,7 @@ class Controller extends \yii\base\Controller
 	 * Prints a string to STDOUT
 	 *
 	 * You may optionally format the string with ANSI codes by
-	 * passing additional parameters using the constants defined in [[yii\helpers\base\Console]].
+	 * passing additional parameters using the constants defined in [[yii\helpers\Console]].
 	 *
 	 * Example:
 	 *
@@ -187,7 +187,7 @@ class Controller extends \yii\base\Controller
 	 * Prints a string to STDERR
 	 *
 	 * You may optionally format the string with ANSI codes by
-	 * passing additional parameters using the constants defined in [[yii\helpers\base\Console]].
+	 * passing additional parameters using the constants defined in [[yii\helpers\Console]].
 	 *
 	 * Example:
 	 *
diff --git a/framework/yii/helpers/ArrayHelper.php b/framework/yii/helpers/ArrayHelper.php
index d58341c..085104b 100644
--- a/framework/yii/helpers/ArrayHelper.php
+++ b/framework/yii/helpers/ArrayHelper.php
@@ -8,12 +8,12 @@
 namespace yii\helpers;
 
 /**
- * ArrayHelper provides additional array functionality you can use in your
+ * ArrayHelper provides additional array functionality that you can use in your
  * application.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class ArrayHelper extends base\ArrayHelper
+class ArrayHelper extends ArrayHelperBase
 {
 }
diff --git a/framework/yii/helpers/base/ArrayHelper.php b/framework/yii/helpers/ArrayHelperBase.php
similarity index 98%
rename from framework/yii/helpers/base/ArrayHelper.php
rename to framework/yii/helpers/ArrayHelperBase.php
index de64f61..aa12700 100644
--- a/framework/yii/helpers/base/ArrayHelper.php
+++ b/framework/yii/helpers/ArrayHelperBase.php
@@ -5,20 +5,21 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Yii;
 use yii\base\Arrayable;
 use yii\base\InvalidParamException;
 
 /**
- * ArrayHelper provides additional array functionality you can use in your
- * application.
+ * ArrayHelperBase provides concrete implementation for [[ArrayHelper]].
+ *
+ * Do not use ArrayHelperBase. Use [[ArrayHelper]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class ArrayHelper
+class ArrayHelperBase
 {
 	/**
 	 * Converts an object or an array of objects into an array.
diff --git a/framework/yii/helpers/Console.php b/framework/yii/helpers/Console.php
index 0055107..eeadcbc 100644
--- a/framework/yii/helpers/Console.php
+++ b/framework/yii/helpers/Console.php
@@ -17,6 +17,6 @@ namespace yii\helpers;
  * @author Carsten Brandt <mail@cebe.cc>
  * @since 2.0
  */
-class Console extends base\Console
+class Console extends ConsoleBase
 {
 }
diff --git a/framework/yii/helpers/base/Console.php b/framework/yii/helpers/ConsoleBase.php
similarity index 98%
rename from framework/yii/helpers/base/Console.php
rename to framework/yii/helpers/ConsoleBase.php
index e3acbd9..2372a64 100644
--- a/framework/yii/helpers/base/Console.php
+++ b/framework/yii/helpers/ConsoleBase.php
@@ -5,27 +5,17 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 /**
- * TODO adjust phpdoc
- * TODO test this on all kinds of terminals, especially windows (check out lib ncurses)
- *
- * Console View is the base class for console view components
- *
- * A console view provides functionality to create rich console application by allowing to format output
- * by adding color and font style to it.
- *
- * The following constants are available for formatting:
- *
- * TODO document constants
- *
+ * ConsoleBase provides concrete implementation for [[Console]].
  *
+ * Do not use ConsoleBase. Use [[Console]] instead.
  *
  * @author Carsten Brandt <mail@cebe.cc>
  * @since 2.0
  */
-class Console
+class ConsoleBase
 {
 	const FG_BLACK  = 30;
 	const FG_RED    = 31;
diff --git a/framework/yii/helpers/FileHelper.php b/framework/yii/helpers/FileHelper.php
index 04ce4e1..9241025 100644
--- a/framework/yii/helpers/FileHelper.php
+++ b/framework/yii/helpers/FileHelper.php
@@ -16,6 +16,6 @@ namespace yii\helpers;
  * @author Alex Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class FileHelper extends base\FileHelper
+class FileHelper extends FileHelperBase
 {
 }
diff --git a/framework/yii/helpers/base/FileHelper.php b/framework/yii/helpers/FileHelperBase.php
similarity index 97%
rename from framework/yii/helpers/base/FileHelper.php
rename to framework/yii/helpers/FileHelperBase.php
index 72aa8bf..6358ea1 100644
--- a/framework/yii/helpers/base/FileHelper.php
+++ b/framework/yii/helpers/FileHelperBase.php
@@ -7,19 +7,20 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Yii;
-use yii\helpers\StringHelper as StringHelper2;
 
 /**
- * Filesystem helper
+ * FileHelperBase provides concrete implementation for [[FileHelper]].
+ *
+ * Do not use FileHelperBase. Use [[FileHelper]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @author Alex Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class FileHelper
+class FileHelperBase
 {
 	/**
 	 * Normalizes a file/directory path.
@@ -279,11 +280,11 @@ class FileHelper
 		if ($isDir = is_dir($path)) {
 			$path .= '/';
 		}
-		$n = StringHelper2::strlen($path);
+		$n = StringHelper::strlen($path);
 
 		if (!empty($options['except'])) {
 			foreach ($options['except'] as $name) {
-				if (StringHelper2::substr($path, -StringHelper2::strlen($name), $n) === $name) {
+				if (StringHelper::substr($path, -StringHelper::strlen($name), $n) === $name) {
 					return false;
 				}
 			}
@@ -291,7 +292,7 @@ class FileHelper
 
 		if (!$isDir && !empty($options['only'])) {
 			foreach ($options['only'] as $name) {
-				if (StringHelper2::substr($path, -StringHelper2::strlen($name), $n) === $name) {
+				if (StringHelper::substr($path, -StringHelper::strlen($name), $n) === $name) {
 					return true;
 				}
 			}
diff --git a/framework/yii/helpers/Html.php b/framework/yii/helpers/Html.php
index b3a0743..8e4f1c9 100644
--- a/framework/yii/helpers/Html.php
+++ b/framework/yii/helpers/Html.php
@@ -13,6 +13,6 @@ namespace yii\helpers;
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Html extends base\Html
+class Html extends HtmlBase
 {
 }
diff --git a/framework/yii/helpers/base/Html.php b/framework/yii/helpers/HtmlBase.php
similarity index 99%
rename from framework/yii/helpers/base/Html.php
rename to framework/yii/helpers/HtmlBase.php
index 42f0b14..b55098f 100644
--- a/framework/yii/helpers/base/Html.php
+++ b/framework/yii/helpers/HtmlBase.php
@@ -5,7 +5,7 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Yii;
 use yii\base\InvalidParamException;
@@ -13,12 +13,14 @@ use yii\web\Request;
 use yii\base\Model;
 
 /**
- * Html provides a set of static methods for generating commonly used HTML tags.
+ * HtmlBase provides concrete implementation for [[Html]].
+ *
+ * Do not use HtmlBase. Use [[Html]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Html
+class HtmlBase
 {
 	/**
 	 * @var array list of void elements (element name => 1)
diff --git a/framework/yii/helpers/HtmlPurifier.php b/framework/yii/helpers/HtmlPurifier.php
index efba874..f7203e4 100644
--- a/framework/yii/helpers/HtmlPurifier.php
+++ b/framework/yii/helpers/HtmlPurifier.php
@@ -32,6 +32,6 @@ namespace yii\helpers;
  * @author Alexander Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class HtmlPurifier extends base\HtmlPurifier
+class HtmlPurifier extends HtmlPurifierBase
 {
 }
diff --git a/framework/yii/helpers/base/HtmlPurifier.php b/framework/yii/helpers/HtmlPurifierBase.php
similarity index 76%
rename from framework/yii/helpers/base/HtmlPurifier.php
rename to framework/yii/helpers/HtmlPurifierBase.php
index 9c4835f..e89a589 100644
--- a/framework/yii/helpers/base/HtmlPurifier.php
+++ b/framework/yii/helpers/HtmlPurifierBase.php
@@ -4,17 +4,17 @@
  * @link http://www.yiiframework.com/
  * @license http://www.yiiframework.com/license/
  */
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 /**
- * HtmlPurifier is the concrete implementation of the [[yii\helpers\HtmlPurifier]] class.
+ * HtmlPurifierBase provides concrete implementation for [[HtmlPurifier]].
  *
- * You should use [[yii\helpers\HtmlPurifier]] instead of this class in your application.
+ * Do not use HtmlPurifierBase. Use [[HtmlPurifier]] instead.
  *
  * @author Alexander Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class HtmlPurifier
+class HtmlPurifierBase
 {
 	/**
 	 * Passes markup through HTMLPurifier making it safe to output to end user
diff --git a/framework/yii/helpers/Inflector.php b/framework/yii/helpers/Inflector.php
index 72f77a7..ba9c069 100644
--- a/framework/yii/helpers/Inflector.php
+++ b/framework/yii/helpers/Inflector.php
@@ -13,6 +13,6 @@ namespace yii\helpers;
  * @author Antonio Ramirez <amigo.cobos@gmail.com>
  * @since 2.0
  */
-class Inflector extends base\Inflector
+class Inflector extends InflectorBase
 {
 }
diff --git a/framework/yii/helpers/base/Inflector.php b/framework/yii/helpers/InflectorBase.php
similarity index 98%
rename from framework/yii/helpers/base/Inflector.php
rename to framework/yii/helpers/InflectorBase.php
index f500c4c..e8d85d6 100644
--- a/framework/yii/helpers/base/Inflector.php
+++ b/framework/yii/helpers/InflectorBase.php
@@ -5,17 +5,19 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Yii;
 
 /**
- * Inflector pluralizes and singularizes English nouns. It also contains some other useful methods.
+ * InflectorBase provides concrete implementation for [[Inflector]].
+ *
+ * Do not use InflectorBase. Use [[Inflector]] instead.
  *
  * @author Antonio Ramirez <amigo.cobos@gmail.com>
  * @since 2.0
  */
-class Inflector
+class InflectorBase
 {
 	/**
 	 * @var array the rules for converting a word into its plural form.
diff --git a/framework/yii/helpers/Json.php b/framework/yii/helpers/Json.php
index 117db1f..424de1f 100644
--- a/framework/yii/helpers/Json.php
+++ b/framework/yii/helpers/Json.php
@@ -8,10 +8,12 @@
 namespace yii\helpers;
 
 /**
- *
+ * Json is a helper class providing JSON data encoding and decoding.
+ * It enhances the PHP built-in functions `json_encode()` and `json_decode()`
+ * by supporting encoding JavaScript expressions and throwing exceptions when decoding fails.
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Json extends base\Json
+class Json extends JsonBase
 {
 }
diff --git a/framework/yii/helpers/base/Json.php b/framework/yii/helpers/JsonBase.php
similarity index 92%
rename from framework/yii/helpers/base/Json.php
rename to framework/yii/helpers/JsonBase.php
index 7d05a4a..fa3fb01 100644
--- a/framework/yii/helpers/base/Json.php
+++ b/framework/yii/helpers/JsonBase.php
@@ -5,20 +5,21 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use yii\base\InvalidParamException;
 use yii\base\Arrayable;
 use yii\web\JsExpression;
 
 /**
- * Json is a helper class providing JSON data encoding and decoding.
- * It enhances the PHP built-in functions `json_encode()` and `json_decode()`
- * by supporting encoding JavaScript expressions and throwing exceptions when decoding fails.
+ * JsonBase provides concrete implementation for [[Json]].
+ *
+ * Do not use JsonBase. Use [[Json]] instead.
+ *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Json
+class JsonBase
 {
 	/**
 	 * Encodes the given value into a JSON string.
diff --git a/framework/yii/helpers/Markdown.php b/framework/yii/helpers/Markdown.php
index 3f6c98e..86df045 100644
--- a/framework/yii/helpers/Markdown.php
+++ b/framework/yii/helpers/Markdown.php
@@ -28,6 +28,6 @@ namespace yii\helpers;
  * @author Alexander Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class Markdown extends base\Markdown
+class Markdown extends MarkdownBase
 {
 }
diff --git a/framework/yii/helpers/base/Markdown.php b/framework/yii/helpers/MarkdownBase.php
similarity index 60%
rename from framework/yii/helpers/base/Markdown.php
rename to framework/yii/helpers/MarkdownBase.php
index 3e69015..9db5b1e 100644
--- a/framework/yii/helpers/base/Markdown.php
+++ b/framework/yii/helpers/MarkdownBase.php
@@ -5,32 +5,19 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Michelf\MarkdownExtra;
 
 /**
- * Markdown provides an ability to transform markdown into HTML.
+ * MarkdownBase provides concrete implementation for [[Markdown]].
  *
- * Basic usage is the following:
+ * Do not use MarkdownBase. Use [[Markdown]] instead.
  *
- * ```php
- * $myHtml = Markdown::process($myText);
- * ```
- *
- * If you want to configure the parser:
- *
- * ```php
- * $myHtml = Markdown::process($myText, array(
- *     'fn_id_prefix' => 'footnote_',
- * ));
- * ```
- *
- * For more details please refer to [PHP Markdown library documentation](http://michelf.ca/projects/php-markdown/).
  * @author Alexander Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class Markdown
+class MarkdownBase
 {
 	/**
 	 * @var MarkdownExtra
diff --git a/framework/yii/helpers/SecurityHelper.php b/framework/yii/helpers/Security.php
similarity index 69%
rename from framework/yii/helpers/SecurityHelper.php
rename to framework/yii/helpers/Security.php
index d16e7e6..d0ca2ed 100644
--- a/framework/yii/helpers/SecurityHelper.php
+++ b/framework/yii/helpers/Security.php
@@ -8,15 +8,15 @@
 namespace yii\helpers;
 
 /**
- * SecurityHelper provides a set of methods to handle common security-related tasks.
+ * Security provides a set of methods to handle common security-related tasks.
  *
- * In particular, SecurityHelper supports the following features:
+ * In particular, Security supports the following features:
  *
  * - Encryption/decryption: [[encrypt()]] and [[decrypt()]]
  * - Data tampering prevention: [[hashData()]] and [[validateData()]]
  * - Password validation: [[generatePasswordHash()]] and [[validatePassword()]]
  *
- * Additionally, SecurityHelper provides [[getSecretKey()]] to support generating
+ * Additionally, Security provides [[getSecretKey()]] to support generating
  * named secret keys. These secret keys, once generated, will be stored in a file
  * and made available in future requests.
  *
@@ -24,6 +24,6 @@ namespace yii\helpers;
  * @author Tom Worster <fsb@thefsb.org>
  * @since 2.0
  */
-class SecurityHelper extends base\SecurityHelper
+class Security extends SecurityBase
 {
 }
diff --git a/framework/yii/helpers/base/SecurityHelper.php b/framework/yii/helpers/SecurityBase.php
similarity index 93%
rename from framework/yii/helpers/base/SecurityHelper.php
rename to framework/yii/helpers/SecurityBase.php
index 546ed21..9b743c4 100644
--- a/framework/yii/helpers/base/SecurityHelper.php
+++ b/framework/yii/helpers/SecurityBase.php
@@ -5,7 +5,7 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 use Yii;
 use yii\base\Exception;
@@ -13,23 +13,15 @@ use yii\base\InvalidConfigException;
 use yii\base\InvalidParamException;
 
 /**
- * SecurityHelper provides a set of methods to handle common security-related tasks.
+ * SecurityBase provides concrete implementation for [[Security]].
  *
- * In particular, SecurityHelper supports the following features:
- *
- * - Encryption/decryption: [[encrypt()]] and [[decrypt()]]
- * - Data tampering prevention: [[hashData()]] and [[validateData()]]
- * - Password validation: [[generatePasswordHash()]] and [[validatePassword()]]
- *
- * Additionally, SecurityHelper provides [[getSecretKey()]] to support generating
- * named secret keys. These secret keys, once generated, will be stored in a file
- * and made available in future requests.
+ * Do not use SecurityBase. Use [[Security]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @author Tom Worster <fsb@thefsb.org>
  * @since 2.0
  */
-class SecurityHelper
+class SecurityBase
 {
 	/**
 	 * Encrypts data.
@@ -182,11 +174,11 @@ class SecurityHelper
 	 *
 	 * ~~~
 	 * // generates the hash (usually done during user registration or when the password is changed)
-	 * $hash = SecurityHelper::generatePasswordHash($password);
+	 * $hash = Security::generatePasswordHash($password);
 	 * // ...save $hash in database...
 	 *
 	 * // during login, validate if the password entered is correct using $hash fetched from database
-	 * if (SecurityHelper::validatePassword($password, $hash) {
+	 * if (Security::validatePassword($password, $hash) {
 	 *     // password is good
 	 * } else {
 	 *     // password is bad
diff --git a/framework/yii/helpers/StringHelper.php b/framework/yii/helpers/StringHelper.php
index 22b881a..ef75790 100644
--- a/framework/yii/helpers/StringHelper.php
+++ b/framework/yii/helpers/StringHelper.php
@@ -14,6 +14,6 @@ namespace yii\helpers;
  * @author Alex Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class StringHelper extends base\StringHelper
+class StringHelper extends StringHelperBase
 {
 }
diff --git a/framework/yii/helpers/base/StringHelper.php b/framework/yii/helpers/StringHelperBase.php
similarity index 92%
rename from framework/yii/helpers/base/StringHelper.php
rename to framework/yii/helpers/StringHelperBase.php
index 7fbb960..e7d1d1e 100644
--- a/framework/yii/helpers/base/StringHelper.php
+++ b/framework/yii/helpers/StringHelperBase.php
@@ -5,16 +5,18 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 /**
- * StringHelper
+ * StringHelperBase provides concrete implementation for [[StringHelper]].
+ *
+ * Do not use StringHelperBase. Use [[StringHelper]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @author Alex Makarov <sam@rmcreative.ru>
  * @since 2.0
  */
-class StringHelper
+class StringHelperBase
 {
 	/**
 	 * Returns the number of bytes in the given string.
diff --git a/framework/yii/helpers/VarDumper.php b/framework/yii/helpers/VarDumper.php
index 59a1718..50e543c 100644
--- a/framework/yii/helpers/VarDumper.php
+++ b/framework/yii/helpers/VarDumper.php
@@ -23,6 +23,6 @@ namespace yii\helpers;
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class VarDumper extends base\VarDumper
+class VarDumper extends VarDumperBase
 {
 }
diff --git a/framework/yii/helpers/base/VarDumper.php b/framework/yii/helpers/VarDumperBase.php
similarity index 90%
rename from framework/yii/helpers/base/VarDumper.php
rename to framework/yii/helpers/VarDumperBase.php
index 730aafe..c7da208 100644
--- a/framework/yii/helpers/base/VarDumper.php
+++ b/framework/yii/helpers/VarDumperBase.php
@@ -6,24 +6,17 @@
  * @license http://www.yiiframework.com/license/
  */
 
-namespace yii\helpers\base;
+namespace yii\helpers;
 
 /**
- * VarDumper is intended to replace the buggy PHP function var_dump and print_r.
- * It can correctly identify the recursively referenced objects in a complex
- * object structure. It also has a recursive depth control to avoid indefinite
- * recursive display of some peculiar variables.
+ * VarDumperBase provides concrete implementation for [[VarDumper]].
  *
- * VarDumper can be used as follows,
- *
- * ~~~
- * VarDumper::dump($var);
- * ~~~
+ * Do not use VarDumperBase. Use [[VarDumper]] instead.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class VarDumper
+class VarDumperBase
 {
 	private static $_objects;
 	private static $_output;
diff --git a/framework/yii/helpers/base/mimeTypes.php b/framework/yii/helpers/mimeTypes.php
similarity index 100%
rename from framework/yii/helpers/base/mimeTypes.php
rename to framework/yii/helpers/mimeTypes.php
diff --git a/framework/yii/web/Request.php b/framework/yii/web/Request.php
index d6b4843..ee716f1 100644
--- a/framework/yii/web/Request.php
+++ b/framework/yii/web/Request.php
@@ -9,7 +9,7 @@ namespace yii\web;
 
 use Yii;
 use yii\base\InvalidConfigException;
-use yii\helpers\SecurityHelper;
+use yii\helpers\Security;
 
 /**
  * @author Qiang Xue <qiang.xue@gmail.com>
@@ -823,7 +823,7 @@ class Request extends \yii\base\Request
 		if ($this->enableCookieValidation) {
 			$key = $this->getCookieValidationKey();
 			foreach ($_COOKIE as $name => $value) {
-				if (is_string($value) && ($value = SecurityHelper::validateData($value, $key)) !== false) {
+				if (is_string($value) && ($value = Security::validateData($value, $key)) !== false) {
 					$cookies[$name] = new Cookie(array(
 						'name' => $name,
 						'value' => @unserialize($value),
@@ -850,7 +850,7 @@ class Request extends \yii\base\Request
 	public function getCookieValidationKey()
 	{
 		if ($this->_cookieValidationKey === null) {
-			$this->_cookieValidationKey = SecurityHelper::getSecretKey(__CLASS__ . '/' . Yii::$app->id);
+			$this->_cookieValidationKey = Security::getSecretKey(__CLASS__ . '/' . Yii::$app->id);
 		}
 		return $this->_cookieValidationKey;
 	}
diff --git a/framework/yii/web/Response.php b/framework/yii/web/Response.php
index 57b5181..5371122 100644
--- a/framework/yii/web/Response.php
+++ b/framework/yii/web/Response.php
@@ -13,7 +13,7 @@ use yii\base\InvalidParamException;
 use yii\helpers\FileHelper;
 use yii\helpers\Html;
 use yii\helpers\Json;
-use yii\helpers\SecurityHelper;
+use yii\helpers\Security;
 use yii\helpers\StringHelper;
 
 /**
@@ -313,7 +313,7 @@ class Response extends \yii\base\Response
 		foreach ($this->getCookies() as $cookie) {
 			$value = $cookie->value;
 			if ($cookie->expire != 1  && isset($validationKey)) {
-				$value = SecurityHelper::hashData(serialize($value), $validationKey);
+				$value = Security::hashData(serialize($value), $validationKey);
 			}
 			setcookie($cookie->name, $value, $cookie->expire, $cookie->path, $cookie->domain, $cookie->secure, $cookie->httpOnly);
 		}
diff --git a/tests/unit/framework/helpers/FileHelperTest.php b/tests/unit/framework/helpers/FileHelperTest.php
index 1fc8d95..4d874de 100644
--- a/tests/unit/framework/helpers/FileHelperTest.php
+++ b/tests/unit/framework/helpers/FileHelperTest.php
@@ -4,7 +4,7 @@ use yii\helpers\FileHelper;
 use yii\test\TestCase;
 
 /**
- * Unit test for [[yii\helpers\base\FileHelper]]
+ * Unit test for [[yii\helpers\FileHelper]]
  * @see FileHelper
  */
 class FileHelperTest extends TestCase