diff --git a/UPGRADE-2.3.md b/UPGRADE-2.3.md
new file mode 100644
index 000000000000..14dc3c1100a8
--- /dev/null
+++ b/UPGRADE-2.3.md
@@ -0,0 +1,19 @@
+UPGRADE FROM 2.2 to 2.3
+=======================
+
+### HttpKernel
+
+ * The `init()` method has to be called after Kernel instanciation.
+
+   Before:
+
+   ```
+   $kernel = new AppKernel('dev', true);
+   ```
+
+   After:
+
+   ```
+   $kernel = new AppKernel('dev', true);
+   $kernel->init();
+   ```
diff --git a/src/Symfony/Component/HttpKernel/Kernel.php b/src/Symfony/Component/HttpKernel/Kernel.php
index 6c6035b69413..346d32834bab 100644
--- a/src/Symfony/Component/HttpKernel/Kernel.php
+++ b/src/Symfony/Component/HttpKernel/Kernel.php
@@ -90,10 +90,15 @@ public function __construct($environment, $debug)
         if ($this->debug) {
             $this->startTime = microtime(true);
         }
-
-        $this->init();
     }
 
+    /**
+     * Initialize the Kernel.
+     * 
+     * This is the right place to deal with PHP ini settings, debugging tools, etc.
+     *
+     * @api
+     */
     public function init()
     {
         ini_set('display_errors', 0);