diff --git a/.travis.yml b/.travis.yml
index d7cd26c59..5c5a8542f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,9 +1,9 @@
 language: php
 
 php:
-  - 5.2
   - 5.3
   - 5.4
+  - 5.5
 
 before_script:
   - sh -c 'if [ $(php -r "echo PHP_MINOR_VERSION;") -le 4 ]; then echo "extension = apc.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini; fi;'
diff --git a/README.md b/README.md
index 5ff9ae6ee..94ae827e3 100644
--- a/README.md
+++ b/README.md
@@ -31,7 +31,7 @@ It runs on *nix and Windows platforms.
 Requirements
 ------------
 
-PHP 5.2.4 and up. See prerequisites on http://symfony.com/legacy/doc/getting-started/1_4/en/02-Prerequisites
+PHP 5.3.4 and up. See prerequisites on http://symfony.com/legacy/doc/getting-started/1_4/en/02-Prerequisites
 
 Installation
 ------------
diff --git a/data/bin/check_configuration.php b/data/bin/check_configuration.php
index 121b24498..a1997d0cf 100644
--- a/data/bin/check_configuration.php
+++ b/data/bin/check_configuration.php
@@ -67,7 +67,7 @@ function get_ini_path()
 
 // mandatory
 echo "\n** Mandatory requirements **\n\n";
-check(version_compare(phpversion(), '5.2.4', '>='), sprintf('PHP version is at least 5.2.4 (%s)', phpversion()), 'Current version is '.phpversion(), true);
+check(version_compare(phpversion(), '5.3.1', '>='), sprintf('PHP version is at least 5.3.1 (%s)', phpversion()), 'Current version is '.phpversion(), true);
 
 // warnings
 echo "\n** Optional checks **\n\n";
@@ -97,8 +97,6 @@ function_exists('xcache_set')
 check(!ini_get('register_globals'), 'php.ini has register_globals set to off', 'Set it to off in php.ini', false);
 check(!ini_get('session.auto_start'), 'php.ini has session.auto_start set to off', 'Set it to off in php.ini', false);
 
-check(version_compare(phpversion(), '5.2.9', '!='), 'PHP version is not 5.2.9', 'PHP 5.2.9 broke array_unique() and sfToolkit::arrayDeepMerge(). Use 5.2.10 instead [Ticket #6211]', false);
-
 if (!is_cli())
 {
   echo '</pre></body></html>';
diff --git a/lib/command/sfCommandManager.class.php b/lib/command/sfCommandManager.class.php
index 12264414d..d7c0b2f63 100644
--- a/lib/command/sfCommandManager.class.php
+++ b/lib/command/sfCommandManager.class.php
@@ -3,7 +3,7 @@
 /*
  * This file is part of the symfony package.
  * (c) 2004-2006 Fabien Potencier <fabien.potencier@symfony-project.com>
- * 
+ *
  * For the full copyright and license information, please view the LICENSE
  * file that was distributed with this source code.
  */
@@ -108,7 +108,9 @@ public function process($arguments = null)
     else if (!is_array($arguments))
     {
       // hack to split arguments with spaces : --test="with some spaces"
-      $arguments = preg_replace('/(\'|")(.+?)\\1/e', "str_replace(' ', '=PLACEHOLDER=', '\\2')", $arguments);
+      $arguments = preg_replace_callback('/(\'|")(.+?)\\1/', function ($match) {
+        return str_replace(' ', '=PLACEHOLDER=', $match[2]);
+      }, $arguments);
       $arguments = preg_split('/\s+/', $arguments);
       $arguments = str_replace('=PLACEHOLDER=', ' ', $arguments);
     }
diff --git a/lib/form/addon/sfFormObject.class.php b/lib/form/addon/sfFormObject.class.php
index 16295630a..3652a511c 100644
--- a/lib/form/addon/sfFormObject.class.php
+++ b/lib/form/addon/sfFormObject.class.php
@@ -285,6 +285,6 @@ public function renderFormTag($url, array $attributes = array())
 
   protected function camelize($text)
   {
-    return preg_replace(array('#/(.?)#e', '/(^|_|-)+(.)/e'), array("'::'.strtoupper('\\1')", "strtoupper('\\2')"), $text);
+    return strtr(ucwords(strtr($text, array('/' => ':: ', '_' => ' ', '-' => ' '))), array(' ' => ''));
   }
 }
diff --git a/lib/plugins/sfDoctrinePlugin/lib/form/sfFormFilterDoctrine.class.php b/lib/plugins/sfDoctrinePlugin/lib/form/sfFormFilterDoctrine.class.php
index 9c2fcfc56..8354e5bf5 100644
--- a/lib/plugins/sfDoctrinePlugin/lib/form/sfFormFilterDoctrine.class.php
+++ b/lib/plugins/sfDoctrinePlugin/lib/form/sfFormFilterDoctrine.class.php
@@ -64,7 +64,7 @@ public function setTableMethod($tableMethod)
 
   /**
    * Sets the query object to use.
-   * 
+   *
    * @param Doctrine_Query $query
    */
   public function setQuery($query)
@@ -290,11 +290,11 @@ protected function setupInheritance()
 
   /**
    * Returns the name of the related model.
-   * 
+   *
    * @param string $alias A relation alias
-   * 
+   *
    * @return string
-   * 
+   *
    * @throws InvalidArgumentException If no relation with the supplied alias exists on the current model
    */
   protected function getRelatedModelName($alias)
@@ -323,7 +323,7 @@ protected function getFieldName($colName)
 
   protected function camelize($text)
   {
-    return sfToolkit::pregtr($text, array('#/(.?)#e' => "'::'.strtoupper('\\1')", '/(^|_|-)+(.)/e' => "strtoupper('\\2')"));
+    return strtr(ucwords(strtr($text, array('/' => ':: ', '_' => ' ', '-' => ' '))), array(' ' => ''));
   }
 
   protected function getTable()
diff --git a/lib/response/sfWebResponse.class.php b/lib/response/sfWebResponse.class.php
index 95e14c477..36dd49102 100644
--- a/lib/response/sfWebResponse.class.php
+++ b/lib/response/sfWebResponse.class.php
@@ -411,7 +411,7 @@ public function send()
    */
   protected function normalizeHeaderName($name)
   {
-    return preg_replace('/\-(.)/e', "'-'.strtoupper('\\1')", strtr(ucfirst(strtolower($name)), '_', '-'));
+    return strtr(ucwords(strtr(strtolower($name), array('_' => ' ', '-' => ' '))), array(' ' => '-'));
   }
 
   /**
diff --git a/lib/service/sfServiceContainer.class.php b/lib/service/sfServiceContainer.class.php
index e6b4deff4..83964ea47 100644
--- a/lib/service/sfServiceContainer.class.php
+++ b/lib/service/sfServiceContainer.class.php
@@ -213,7 +213,7 @@ public function getServiceIds()
 
   static public function camelize($id)
   {
-    return preg_replace(array('/(^|_|-)+(.)/e', '/\.(.)/e'), array("strtoupper('\\2')", "'_'.strtoupper('\\1')"), $id);
+    return strtr(ucwords(strtr($id, array('_' => ' ', '-' => ' ', '.' => '_ '))), array(' ' => ''));
   }
 
   static public function underscore($id)
diff --git a/lib/util/sfInflector.class.php b/lib/util/sfInflector.class.php
index 50c1673d5..73b7b48e4 100644
--- a/lib/util/sfInflector.class.php
+++ b/lib/util/sfInflector.class.php
@@ -27,11 +27,8 @@ class sfInflector
    */
   public static function camelize($lower_case_and_underscored_word)
   {
-    $tmp = $lower_case_and_underscored_word;
-    $tmp = sfToolkit::pregtr($tmp, array('#/(.?)#e'    => "'::'.strtoupper('\\1')",
-                                         '/(^|_|-)+(.)/e' => "strtoupper('\\2')"));
 
-    return $tmp;
+    return strtr(ucwords(strtr($lower_case_and_underscored_word, array('/' => ':: ', '_' => ' ', '-' => ' '))), array(' ' => ''));
   }
 
   /**
diff --git a/lib/util/sfToolkit.class.php b/lib/util/sfToolkit.class.php
index 43762a19f..a471c97ea 100644
--- a/lib/util/sfToolkit.class.php
+++ b/lib/util/sfToolkit.class.php
@@ -348,7 +348,14 @@ public static function literalize($value, $quoted = false)
    */
   public static function replaceConstants($value)
   {
-    return is_string($value) ? preg_replace_callback('/%(.+?)%/', create_function('$v', 'return sfConfig::has(strtolower($v[1])) ? sfConfig::get(strtolower($v[1])) : "%{$v[1]}%";'), $value) : $value;
+    if (!is_string($value))
+    {
+      return $value;
+    }
+
+    return preg_replace_callback('/%(.+?)%/', function ($v) {
+      return sfConfig::has(strtolower($v[1])) ? sfConfig::get(strtolower($v[1])) : '%'.$v[1].'%';
+    }, $value);
   }
 
   /**
diff --git a/lib/vendor/lime/lime.php b/lib/vendor/lime/lime.php
index 7a2ca5788..f62e5c97c 100644
--- a/lib/vendor/lime/lime.php
+++ b/lib/vendor/lime/lime.php
@@ -684,10 +684,35 @@ public function echoln($message, $colorizer_parameter = null, $colorize = true)
   {
     if ($colorize)
     {
-      $message = preg_replace('/(?:^|\.)((?:not ok|dubious|errors) *\d*)\b/e', '$this->colorizer->colorize(\'$1\', \'ERROR\')', $message);
-      $message = preg_replace('/(?:^|\.)(ok *\d*)\b/e', '$this->colorizer->colorize(\'$1\', \'INFO\')', $message);
-      $message = preg_replace('/"(.+?)"/e', '$this->colorizer->colorize(\'$1\', \'PARAMETER\')', $message);
-      $message = preg_replace('/(\->|\:\:)?([a-zA-Z0-9_]+?)\(\)/e', '$this->colorizer->colorize(\'$1$2()\', \'PARAMETER\')', $message);
+      $colorizer = $this->colorizer;
+      $message = preg_replace_callback(
+        '/(?:^|\.)((?:not ok|dubious|errors) *\d*)\b/',
+        function ($match) use ($colorizer) {
+          return $colorizer->colorize($match[1], 'ERROR');
+        },
+        $message
+      );
+      $message = preg_replace_callback(
+        '/(?:^|\.)(ok *\d*)\b/',
+        function ($match) use ($colorizer) {
+          return $colorizer->colorize($match[1], 'INFO');
+        },
+        $message
+      );
+      $message = preg_replace_callback(
+        '/"(.+?)"/',
+        function ($match) use ($colorizer) {
+          return $colorizer->colorize($match[1], 'PARAMETER');
+        },
+        $message
+      );
+      $message = preg_replace_callback(
+        '/(\->|\:\:)?([a-zA-Z0-9_]+?)\(\)/',
+        function ($match) use ($colorizer) {
+          return $colorizer->colorize($match[1].$match[2].'()', 'PARAMETER');
+        },
+        $message
+      );
     }
 
     echo ($colorizer_parameter ? $this->colorizer->colorize($message, $colorizer_parameter) : $message)."\n";