diff --git a/UPDATE.md b/UPDATE.md
index 0b1ae8c56c..71fab00426 100644
--- a/UPDATE.md
+++ b/UPDATE.md
@@ -9,7 +9,72 @@ timeline closely anyway.
beta3 to beta4
--------------
-* Form DateType parameter single-text changed to single_text
+* The event system has been made more flexible. A listener can now be any
+ valid PHP callable.
+
+ * `EventDispatcher::addListener($eventName, $listener, $priority = 0)`:
+ `$eventName` is the event name (cannot be an array anymore) and
+ `$listener` is a PHP callable.
+
+ * The events classes and constants have been renamed:
+
+ * `Symfony\Component\Form\Events` to `Symfony\Component\Form\FormEvents`
+
+ -Events::preBind = 'preBind'
+ -Events::postBind = 'postBind'
+ -Events::preSetData = 'preSetData'
+ -Events::postSetData = 'postSetData'
+ -Events::onBindClientData = 'onBindClientData'
+ -Events::onBindNormData = 'onBindNormData'
+ -Events::onSetData = 'onSetData'
+
+ +FormEvents::PRE_BIND = 'form.pre_bind'
+ +FormEvents::POST_BIND = 'form.post_bind'
+ +FormEvents::PRE_SET_DATA = 'form.pre_set_data'
+ +FormEvents::POST_SET_DATA = 'form.post_set_data'
+ +FormEvents::ON_BIND_CLIENT_DATA = 'form.on_bind_client_data'
+ +FormEvents::ON_BIND_NORM_DATA = 'form.on_bind_norm_data'
+ +FormEvents::ON_SET_DATA = 'form.on_set_data'
+
+ * `Symfony\Component\HttpKernel\Events` to `Symfony\Component\HttpKernel\CoreEvents`
+
+ -Events::onCoreRequest = 'onCoreRequest'
+ -Events::onCoreException = 'onCoreException'
+ -Events::onCoreView = 'onCoreView'
+ -Events::onCoreController = 'onCoreController'
+ -Events::onCoreResponse = 'onCoreResponse'
+
+ +CoreEvents::REQUEST = 'core.request'
+ +CoreEvents::EXCEPTION = 'core.exception'
+ +CoreEvents::VIEW = 'core.view'
+ +CoreEvents::CONTROLLER = 'core.controller'
+ +CoreEvents::RESPONSE = 'core.response'
+
+ * `Symfony\Component\Security\Http\Events` to `Symfony\Component\Security\Http\SecurityEvents`
+
+ -Events::onSecurityInteractiveLogin = 'onSecurityInteractiveLogin'
+ -Events::onSecuritySwitchUser = 'onSecuritySwitchUser'
+
+ +SecurityEvents::INTERACTIVE_LOGIN = 'security.interactive_login'
+ +SecurityEvents::SWITCH_USER = 'security.switch_user'
+
+ * `addListenerService` now only takes a single event name as its first
+ argument.
+
+ * Tags in configuration must now set the method to call:
+
+ -
+ +
+
+ * Subscribers must now always return a hash:
+
+ public static function getSubscribedEvents()
+ {
+ - return Events::onBindNormData;
+ + return array(FormEvents::ON_BIND_NORM_DATA, 'onBindNormData');
+ }
+
+* Form DateType parameter single-text changed to single_text
beta2 to beta3
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