diff --git a/build/controllers/PhpDocController.php b/build/controllers/PhpDocController.php
index ecde1e5618..e711fb6604 100644
--- a/build/controllers/PhpDocController.php
+++ b/build/controllers/PhpDocController.php
@@ -43,7 +43,7 @@ class PhpDocController extends Controller
 	{
 		$except = [];
 		if ($root === null) {
-			$root = dirname(dirname(YII_PATH));
+			$root = dirname(YII_PATH);
 			$extensionPath = "$root/extensions";
 			foreach (scandir($extensionPath) as $extension) {
 				if (ctype_alpha($extension) && is_dir($extensionPath . '/' . $extension)) {
diff --git a/extensions/apidoc/helpers/Markdown.php b/extensions/apidoc/helpers/Markdown.php
index 6139b15e62..7c1800a8b5 100644
--- a/extensions/apidoc/helpers/Markdown.php
+++ b/extensions/apidoc/helpers/Markdown.php
@@ -32,7 +32,7 @@ class Markdown extends \yii\helpers\Markdown
 	 * @param TypeDoc $context
 	 * @return string
 	 */
-	public static function process($content, $context)
+	public static function process($content, $context = null)
 	{
 		$content = trim(parent::process($content, []));
 		if (!strncmp($content, '<p>', 3) && substr($content, -4, 4) == '</p>') {
@@ -77,4 +77,4 @@ class Markdown extends \yii\helpers\Markdown
 
 		return $content;
 	}
-}
\ No newline at end of file
+}
diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index fd54fcd02f..07e2103989 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -81,6 +81,8 @@ Yii Framework 2 Change Log
 - Chg: Changed the signature of `urlCreator` and button creators for `yii\gridview\ActionColumn` (qiangxue)
 - Chg: Updated HTMLPurified dependency to `4.6.*`.
 - Chg: Changed Yii autoloader to support loading PSR-4 classes only (i.e. PEAR-styled classes not supported anymore) (qiangxue)
+- Chg: Changed the directory structure of the framework repository according to PSR-4.
+       You have to update your applications index.php and yii console file to point to the right location for Yii.php
 - Chg: Advanced app template: moved database connection DSN, login and password to `-local` config not to expose it to VCS (samdark)
 - New #66: [Auth client library](https://github.com/yiisoft/yii2-authclient) OpenId, OAuth1, OAuth2 clients (klimov-paul)
 - New #1393: [Codeception testing framework integration](https://github.com/yiisoft/yii2-codeception) (Ragazzo)
diff --git a/framework/classes.php b/framework/classes.php
index 9606930c2c..296dda2034 100644
--- a/framework/classes.php
+++ b/framework/classes.php
@@ -30,6 +30,7 @@ return [
 	'yii\base\InvalidConfigException' => YII_PATH . '/base/InvalidConfigException.php',
 	'yii\base\InvalidParamException' => YII_PATH . '/base/InvalidParamException.php',
 	'yii\base\InvalidRouteException' => YII_PATH . '/base/InvalidRouteException.php',
+	'yii\base\MailEvent' => YII_PATH . '/base/MailEvent.php',
 	'yii\base\Model' => YII_PATH . '/base/Model.php',
 	'yii\base\ModelEvent' => YII_PATH . '/base/ModelEvent.php',
 	'yii\base\Module' => YII_PATH . '/base/Module.php',
@@ -108,6 +109,8 @@ return [
 	'yii\db\mssql\TableSchema' => YII_PATH . '/db/mssql/TableSchema.php',
 	'yii\db\mysql\QueryBuilder' => YII_PATH . '/db/mysql/QueryBuilder.php',
 	'yii\db\mysql\Schema' => YII_PATH . '/db/mysql/Schema.php',
+	'yii\db\oci\QueryBuilder' => YII_PATH . '/db/oci/QueryBuilder.php',
+	'yii\db\oci\Schema' => YII_PATH . '/db/oci/Schema.php',
 	'yii\db\pgsql\QueryBuilder' => YII_PATH . '/db/pgsql/QueryBuilder.php',
 	'yii\db\pgsql\Schema' => YII_PATH . '/db/pgsql/Schema.php',
 	'yii\db\sqlite\QueryBuilder' => YII_PATH . '/db/sqlite/QueryBuilder.php',
@@ -220,7 +223,6 @@ return [
 	'yii\web\PageCache' => YII_PATH . '/web/PageCache.php',
 	'yii\web\Request' => YII_PATH . '/web/Request.php',
 	'yii\web\Response' => YII_PATH . '/web/Response.php',
-	'yii\web\ResponseEvent' => YII_PATH . '/web/ResponseEvent.php',
 	'yii\web\ResponseFormatterInterface' => YII_PATH . '/web/ResponseFormatterInterface.php',
 	'yii\web\Session' => YII_PATH . '/web/Session.php',
 	'yii\web\SessionIterator' => YII_PATH . '/web/SessionIterator.php',
diff --git a/framework/helpers/BaseJson.php b/framework/helpers/BaseJson.php
index ce65f8d7ca..bf62e8b37f 100644
--- a/framework/helpers/BaseJson.php
+++ b/framework/helpers/BaseJson.php
@@ -81,18 +81,20 @@ class BaseJson
 	 */
 	protected static function processData($data, &$expressions, $expPrefix)
 	{
-		if ($data instanceof \JsonSerializable) {
-			$data = $data->jsonSerialize();
-		}
-
 		if (is_object($data)) {
 			if ($data instanceof JsExpression) {
 				$token = "!{[$expPrefix=" . count($expressions) . ']}!';
 				$expressions['"' . $token . '"'] = $data->expression;
 				return $token;
+			} elseif ($data instanceof \JsonSerializable) {
+				$data = $data->jsonSerialize();
+			} elseif ($data instanceof Arrayable) {
+				$data = $data->toArray();
+			} else {
+				$data = get_object_vars($data);
 			}
-			$data = $data instanceof Arrayable ? $data->toArray() : get_object_vars($data);
-			if ($data === [] && !$data instanceof Arrayable) {
+
+			if ($data === []) {
 				return new \stdClass();
 			}
 		}