diff --git a/composer.json b/composer.json
index b9b9a193ba..d7a70e81c0 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,13 @@
         "twig/twig": "~1.20|~2.0",
         "psr/log": "~1.0",
         "symfony/security-acl": "~2.7",
-        "paragonie/random_compat": "~1.0"
+        "symfony/polyfill-intl-icu": "~1.0",
+        "symfony/polyfill-mbstring": "~1.0",
+        "symfony/polyfill-php54": "~1.0",
+        "symfony/polyfill-php55": "~1.0",
+        "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-php70": "~1.0",
+        "symfony/polyfill-util": "~1.0"
     },
     "replace": {
         "symfony/asset": "self.version",
@@ -77,7 +83,6 @@
         "doctrine/orm": "~2.4,>=2.4.5",
         "doctrine/doctrine-bundle": "~1.2",
         "monolog/monolog": "~1.11",
-        "ircmaxell/password-compat": "~1.0",
         "ocramius/proxy-manager": "~0.4|~1.0",
         "egulias/email-validator": "~1.2",
         "phpdocumentor/reflection": "^1.0.7"
@@ -96,10 +101,8 @@
             "Symfony\\Component\\": "src/Symfony/Component/"
         },
         "classmap": [
-            "src/Symfony/Component/HttpFoundation/Resources/stubs",
             "src/Symfony/Component/Intl/Resources/stubs"
-        ],
-        "files": [ "src/Symfony/Component/Intl/Resources/stubs/functions.php" ]
+        ]
     },
     "minimum-stability": "dev",
     "extra": {
diff --git a/src/Symfony/Bridge/Doctrine/Logger/DbalLogger.php b/src/Symfony/Bridge/Doctrine/Logger/DbalLogger.php
index 2d834d7d40..51f9f75e4b 100644
--- a/src/Symfony/Bridge/Doctrine/Logger/DbalLogger.php
+++ b/src/Symfony/Bridge/Doctrine/Logger/DbalLogger.php
@@ -99,16 +99,9 @@ class DbalLogger implements SQLLogger
             }
 
             // detect if the too long string must be shorten
-            if (function_exists('mb_strlen')) {
-                if (self::MAX_STRING_LENGTH < mb_strlen($params[$index], 'UTF-8')) {
-                    $params[$index] = mb_substr($params[$index], 0, self::MAX_STRING_LENGTH - 6, 'UTF-8').' [...]';
-                    continue;
-                }
-            } else {
-                if (self::MAX_STRING_LENGTH < strlen($params[$index])) {
-                    $params[$index] = substr($params[$index], 0, self::MAX_STRING_LENGTH - 6).' [...]';
-                    continue;
-                }
+            if (self::MAX_STRING_LENGTH < iconv_strlen($params[$index], 'UTF-8')) {
+                $params[$index] = iconv_substr($params[$index], 0, self::MAX_STRING_LENGTH - 6, 'UTF-8').' [...]';
+                continue;
             }
         }
 
diff --git a/src/Symfony/Bridge/Doctrine/Tests/Logger/DbalLoggerTest.php b/src/Symfony/Bridge/Doctrine/Tests/Logger/DbalLoggerTest.php
index 9141e9a2d3..74afda32eb 100644
--- a/src/Symfony/Bridge/Doctrine/Tests/Logger/DbalLoggerTest.php
+++ b/src/Symfony/Bridge/Doctrine/Tests/Logger/DbalLoggerTest.php
@@ -132,9 +132,6 @@ class DbalLoggerTest extends \PHPUnit_Framework_TestCase
         ));
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testLogUTF8LongString()
     {
         $logger = $this->getMock('Psr\\Log\\LoggerInterface');
@@ -160,7 +157,7 @@ class DbalLoggerTest extends \PHPUnit_Framework_TestCase
         $dbalLogger
             ->expects($this->once())
             ->method('log')
-            ->with('SQL', array('short' => $shortString, 'long' => mb_substr($longString, 0, DbalLogger::MAX_STRING_LENGTH - 6, mb_detect_encoding($longString)).' [...]'))
+            ->with('SQL', array('short' => $shortString, 'long' => iconv_substr($longString, 0, DbalLogger::MAX_STRING_LENGTH - 6, 'UTF-8').' [...]'))
         ;
 
         $dbalLogger->startQuery('SQL', array(
diff --git a/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php b/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
index 367cc826dc..330cad105b 100644
--- a/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
+++ b/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
@@ -24,7 +24,6 @@ class SymfonyTestsListener extends \PHPUnit_Framework_BaseTestListener
     private $skippedFile = false;
     private $wasSkipped = array();
     private $isSkipped = array();
-    private $testsStack = array();
 
     public function __destruct()
     {
diff --git a/src/Symfony/Bridge/Twig/composer.json b/src/Symfony/Bridge/Twig/composer.json
index e33589122f..a76006086a 100644
--- a/src/Symfony/Bridge/Twig/composer.json
+++ b/src/Symfony/Bridge/Twig/composer.json
@@ -24,7 +24,7 @@
         "symfony/finder": "~2.3|~3.0.0",
         "symfony/form": "~2.8",
         "symfony/http-kernel": "~2.8|~3.0.0",
-        "symfony/intl": "~2.3|~3.0.0",
+        "symfony/polyfill-intl-icu": "~1.0",
         "symfony/routing": "~2.2|~3.0.0",
         "symfony/templating": "~2.1|~3.0.0",
         "symfony/translation": "~2.7|~3.0.0",
diff --git a/src/Symfony/Bundle/FrameworkBundle/Command/TranslationDebugCommand.php b/src/Symfony/Bundle/FrameworkBundle/Command/TranslationDebugCommand.php
index 1608010116..da99cf1d29 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Command/TranslationDebugCommand.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Command/TranslationDebugCommand.php
@@ -240,7 +240,7 @@ EOF
     {
         $string = trim(preg_replace('/\s+/', ' ', $string));
 
-        if (function_exists('mb_strlen') && false !== $encoding = mb_detect_encoding($string)) {
+        if (false !== $encoding = mb_detect_encoding($string, null, true)) {
             if (mb_strlen($string, $encoding) > $length) {
                 return mb_substr($string, 0, $length - 3, $encoding).'...';
             }
diff --git a/src/Symfony/Bundle/FrameworkBundle/composer.json b/src/Symfony/Bundle/FrameworkBundle/composer.json
index d53e785a7e..cf9b510b34 100644
--- a/src/Symfony/Bundle/FrameworkBundle/composer.json
+++ b/src/Symfony/Bundle/FrameworkBundle/composer.json
@@ -24,6 +24,7 @@
         "symfony/event-dispatcher": "~2.8|~3.0.0",
         "symfony/http-foundation": "~2.4.9|~2.5,>=2.5.4|~3.0.0",
         "symfony/http-kernel": "~2.8",
+        "symfony/polyfill-mbstring": "~1.0",
         "symfony/filesystem": "~2.3|~3.0.0",
         "symfony/routing": "~2.8|~3.0.0",
         "symfony/security-core": "~2.6|~3.0.0",
@@ -40,7 +41,7 @@
         "symfony/css-selector": "~2.0,>=2.0.5|~3.0.0",
         "symfony/dom-crawler": "~2.0,>=2.0.5|~3.0.0",
         "symfony/finder": "~2.0,>=2.0.5|~3.0.0",
-        "symfony/intl": "~2.3|~3.0.0",
+        "symfony/polyfill-intl-icu": "~1.0",
         "symfony/security": "~2.6|~3.0.0",
         "symfony/form": "~2.8",
         "symfony/expression-language": "~2.6|~3.0.0",
diff --git a/src/Symfony/Bundle/SecurityBundle/composer.json b/src/Symfony/Bundle/SecurityBundle/composer.json
index 256652dafa..7c6b9dc98d 100644
--- a/src/Symfony/Bundle/SecurityBundle/composer.json
+++ b/src/Symfony/Bundle/SecurityBundle/composer.json
@@ -23,7 +23,6 @@
     },
     "require-dev": {
         "symfony/browser-kit": "~2.4|~3.0.0",
-        "symfony/config": "~2.8|~3.0.0",
         "symfony/console": "~2.7|~3.0.0",
         "symfony/css-selector": "~2.0,>=2.0.5|~3.0.0",
         "symfony/dom-crawler": "~2.0,>=2.0.5|~3.0.0",
@@ -37,8 +36,7 @@
         "symfony/yaml": "~2.0,>=2.0.5|~3.0.0",
         "symfony/expression-language": "~2.6|~3.0.0",
         "doctrine/doctrine-bundle": "~1.2",
-        "twig/twig": "~1.20|~2.0",
-        "ircmaxell/password-compat": "~1.0"
+        "twig/twig": "~1.20|~2.0"
     },
     "autoload": {
         "psr-4": { "Symfony\\Bundle\\SecurityBundle\\": "" }
diff --git a/src/Symfony/Component/Console/Application.php b/src/Symfony/Component/Console/Application.php
index 71ac6aed41..1f398622bf 100644
--- a/src/Symfony/Component/Console/Application.php
+++ b/src/Symfony/Component/Console/Application.php
@@ -1077,11 +1077,7 @@ class Application
 
     private function stringWidth($string)
     {
-        if (!function_exists('mb_strwidth')) {
-            return strlen($string);
-        }
-
-        if (false === $encoding = mb_detect_encoding($string)) {
+        if (false === $encoding = mb_detect_encoding($string, null, true)) {
             return strlen($string);
         }
 
@@ -1094,11 +1090,7 @@ class Application
         // additionally, array_slice() is not enough as some character has doubled width.
         // we need a function to split string not by character count but by string width
 
-        if (!function_exists('mb_strwidth')) {
-            return str_split($string, $width);
-        }
-
-        if (false === $encoding = mb_detect_encoding($string)) {
+        if (false === $encoding = mb_detect_encoding($string, null, true)) {
             return str_split($string, $width);
         }
 
diff --git a/src/Symfony/Component/Console/Helper/Helper.php b/src/Symfony/Component/Console/Helper/Helper.php
index b288d446bd..b542be3a66 100644
--- a/src/Symfony/Component/Console/Helper/Helper.php
+++ b/src/Symfony/Component/Console/Helper/Helper.php
@@ -51,11 +51,7 @@ abstract class Helper implements HelperInterface
      */
     public static function strlen($string)
     {
-        if (!function_exists('mb_strwidth')) {
-            return strlen($string);
-        }
-
-        if (false === $encoding = mb_detect_encoding($string)) {
+        if (false === $encoding = mb_detect_encoding($string, null, true)) {
             return strlen($string);
         }
 
diff --git a/src/Symfony/Component/Console/Helper/Table.php b/src/Symfony/Component/Console/Helper/Table.php
index 5d89b59a8b..db41f092fa 100644
--- a/src/Symfony/Component/Console/Helper/Table.php
+++ b/src/Symfony/Component/Console/Helper/Table.php
@@ -351,7 +351,7 @@ class Table
         }
 
         // str_pad won't work properly with multi-byte strings, we need to fix the padding
-        if (function_exists('mb_strwidth') && false !== $encoding = mb_detect_encoding($cell)) {
+        if (false !== $encoding = mb_detect_encoding($cell, null, true)) {
             $width += strlen($cell) - mb_strwidth($cell, $encoding);
         }
 
diff --git a/src/Symfony/Component/Console/Tests/ApplicationTest.php b/src/Symfony/Component/Console/Tests/ApplicationTest.php
index e98ceb3e02..c5e16088b2 100644
--- a/src/Symfony/Component/Console/Tests/ApplicationTest.php
+++ b/src/Symfony/Component/Console/Tests/ApplicationTest.php
@@ -558,9 +558,6 @@ class ApplicationTest extends \PHPUnit_Framework_TestCase
         $this->assertStringEqualsFile(self::$fixturesPath.'/application_renderexception4.txt', $tester->getDisplay(true), '->renderException() wraps messages when they are bigger than the terminal');
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testRenderExceptionWithDoubleWidthCharacters()
     {
         $application = $this->getMock('Symfony\Component\Console\Application', array('getTerminalWidth'));
diff --git a/src/Symfony/Component/Console/Tests/Helper/FormatterHelperTest.php b/src/Symfony/Component/Console/Tests/Helper/FormatterHelperTest.php
index 15b53e1da6..e0aa9211d3 100644
--- a/src/Symfony/Component/Console/Tests/Helper/FormatterHelperTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/FormatterHelperTest.php
@@ -52,9 +52,6 @@ class FormatterHelperTest extends \PHPUnit_Framework_TestCase
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testFormatBlockWithDiacriticLetters()
     {
         $formatter = new FormatterHelper();
@@ -68,9 +65,6 @@ class FormatterHelperTest extends \PHPUnit_Framework_TestCase
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testFormatBlockWithDoubleWidthDiacriticLetters()
     {
         $formatter = new FormatterHelper();
diff --git a/src/Symfony/Component/Console/Tests/Helper/LegacyProgressHelperTest.php b/src/Symfony/Component/Console/Tests/Helper/LegacyProgressHelperTest.php
index 7c866e8570..f835a71e77 100644
--- a/src/Symfony/Component/Console/Tests/Helper/LegacyProgressHelperTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/LegacyProgressHelperTest.php
@@ -155,9 +155,6 @@ class LegacyProgressHelperTest extends \PHPUnit_Framework_TestCase
         $progress->advance(1);
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testMultiByteSupport()
     {
         $progress = new ProgressHelper();
diff --git a/src/Symfony/Component/Console/Tests/Helper/LegacyTableHelperTest.php b/src/Symfony/Component/Console/Tests/Helper/LegacyTableHelperTest.php
index 02c6d7f6e2..3838e00712 100644
--- a/src/Symfony/Component/Console/Tests/Helper/LegacyTableHelperTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/LegacyTableHelperTest.php
@@ -256,9 +256,6 @@ TABLE
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testRenderMultiByte()
     {
         $table = new TableHelper();
@@ -282,9 +279,6 @@ TABLE;
         $this->assertEquals($expected, $this->getOutputContent($output));
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testRenderFullWidthCharacters()
     {
         $table = new TableHelper();
diff --git a/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php b/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
index e22734a29e..16a4bba54b 100644
--- a/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php
@@ -307,9 +307,6 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         $bar->advance(1);
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testMultiByteSupport()
     {
         $bar = new ProgressBar($output = $this->getOutputStream());
@@ -541,9 +538,6 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testAnsiColorsAndEmojis()
     {
         $bar = new ProgressBar($output = $this->getOutputStream(), 15);
diff --git a/src/Symfony/Component/Console/Tests/Helper/TableTest.php b/src/Symfony/Component/Console/Tests/Helper/TableTest.php
index 4f89a9938f..5a33b7d2f9 100644
--- a/src/Symfony/Component/Console/Tests/Helper/TableTest.php
+++ b/src/Symfony/Component/Console/Tests/Helper/TableTest.php
@@ -464,9 +464,6 @@ TABLE
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testRenderMultiByte()
     {
         $table = new Table($output = $this->getOutputStream());
diff --git a/src/Symfony/Component/Console/composer.json b/src/Symfony/Component/Console/composer.json
index 9ed17c30d3..d8500b47ea 100644
--- a/src/Symfony/Component/Console/composer.json
+++ b/src/Symfony/Component/Console/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
         "symfony/event-dispatcher": "~2.1|~3.0.0",
diff --git a/src/Symfony/Component/DomCrawler/Crawler.php b/src/Symfony/Component/DomCrawler/Crawler.php
index ece2e9847a..c238352f21 100644
--- a/src/Symfony/Component/DomCrawler/Crawler.php
+++ b/src/Symfony/Component/DomCrawler/Crawler.php
@@ -173,34 +173,7 @@ class Crawler extends \SplObjectStorage
 
         try {
             // Convert charset to HTML-entities to work around bugs in DOMDocument::loadHTML()
-
-            if (function_exists('mb_convert_encoding')) {
-                $content = mb_convert_encoding($content, 'HTML-ENTITIES', $charset);
-            } elseif (function_exists('iconv')) {
-                $content = preg_replace_callback(
-                    '/[\x80-\xFF]+/',
-                    function ($m) {
-                        $m = unpack('C*', $m[0]);
-                        $i = 1;
-                        $entities = '';
-
-                        while (isset($m[$i])) {
-                            if (0xF0 <= $m[$i]) {
-                                $c = (($m[$i++] - 0xF0) << 18) + (($m[$i++] - 0x80) << 12) + (($m[$i++] - 0x80) << 6) + $m[$i++] - 0x80;
-                            } elseif (0xE0 <= $m[$i]) {
-                                $c = (($m[$i++] - 0xE0) << 12) + (($m[$i++] - 0x80) << 6) + $m[$i++]  - 0x80;
-                            } else {
-                                $c = (($m[$i++] - 0xC0) << 6) + $m[$i++] - 0x80;
-                            }
-
-                            $entities .= '&#'.$c.';';
-                        }
-
-                        return $entities;
-                    },
-                    iconv($charset, 'UTF-8', $content)
-                );
-            }
+            $content = mb_convert_encoding($content, 'HTML-ENTITIES', $charset);
         } catch (\Exception $e) {
         }
 
diff --git a/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php b/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
index de8e217aee..ecdfc0fe23 100755
--- a/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
+++ b/src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
@@ -102,7 +102,6 @@ class CrawlerTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @covers Symfony\Component\DomCrawler\Crawler::addHtmlContent
-     * @requires extension mbstring
      */
     public function testAddHtmlContentCharset()
     {
@@ -137,7 +136,6 @@ class CrawlerTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @covers Symfony\Component\DomCrawler\Crawler::addHtmlContent
-     * @requires extension mbstring
      */
     public function testAddHtmlContentCharsetGbk()
     {
diff --git a/src/Symfony/Component/DomCrawler/composer.json b/src/Symfony/Component/DomCrawler/composer.json
index 5e3922fe8e..ce2aa8fd6a 100644
--- a/src/Symfony/Component/DomCrawler/composer.json
+++ b/src/Symfony/Component/DomCrawler/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
         "symfony/css-selector": "~2.8|~3.0.0"
diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
index 8aef383fe4..0c7c327f48 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php
@@ -197,7 +197,7 @@ class NumberToLocalizedStringTransformer implements DataTransformerInterface
             throw new TransformationFailedException('I don\'t have a clear idea what infinity looks like');
         }
 
-        if (function_exists('mb_detect_encoding') && false !== $encoding = mb_detect_encoding($value)) {
+        if (false !== $encoding = mb_detect_encoding($value, null, true)) {
             $length = mb_strlen($value, $encoding);
             $remainder = mb_substr($value, $position, $length, $encoding);
         } else {
diff --git a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
index 02131f68c4..2a47178dad 100644
--- a/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
+++ b/src/Symfony/Component/Form/Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php
@@ -238,8 +238,6 @@ class NumberToLocalizedStringTransformerTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @see https://github.com/symfony/symfony/issues/7609
-     *
-     * @requires extension mbstring
      */
     public function testReverseTransformWithGroupingAndFixedSpaces()
     {
@@ -583,7 +581,6 @@ class NumberToLocalizedStringTransformerTest extends \PHPUnit_Framework_TestCase
     /**
      * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
      * @expectedExceptionMessage The number contains unrecognized characters: "foo8"
-     * @requires extension mbstring
      */
     public function testReverseTransformDisallowsCenteredExtraCharactersMultibyte()
     {
@@ -600,7 +597,6 @@ class NumberToLocalizedStringTransformerTest extends \PHPUnit_Framework_TestCase
     /**
      * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
      * @expectedExceptionMessage The number contains unrecognized characters: "foo8"
-     * @requires extension mbstring
      */
     public function testReverseTransformIgnoresTrailingSpacesInExceptionMessage()
     {
@@ -628,7 +624,6 @@ class NumberToLocalizedStringTransformerTest extends \PHPUnit_Framework_TestCase
     /**
      * @expectedException \Symfony\Component\Form\Exception\TransformationFailedException
      * @expectedExceptionMessage The number contains unrecognized characters: "foo"
-     * @requires extension mbstring
      */
     public function testReverseTransformDisallowsTrailingExtraCharactersMultibyte()
     {
diff --git a/src/Symfony/Component/Form/Tests/Util/StringUtilTest.php b/src/Symfony/Component/Form/Tests/Util/StringUtilTest.php
index ddbafe49dc..bd9b28c46e 100644
--- a/src/Symfony/Component/Form/Tests/Util/StringUtilTest.php
+++ b/src/Symfony/Component/Form/Tests/Util/StringUtilTest.php
@@ -24,7 +24,6 @@ class StringUtilTest extends \PHPUnit_Framework_TestCase
 
     /**
      * @dataProvider spaceProvider
-     * @requires extension mbstring
      */
     public function testTrimUtf8Separators($hex)
     {
diff --git a/src/Symfony/Component/Form/composer.json b/src/Symfony/Component/Form/composer.json
index 307b383610..dd43dcd3c2 100644
--- a/src/Symfony/Component/Form/composer.json
+++ b/src/Symfony/Component/Form/composer.json
@@ -20,6 +20,7 @@
         "symfony/event-dispatcher": "~2.1|~3.0.0",
         "symfony/intl": "~2.4|~3.0.0",
         "symfony/options-resolver": "~2.6",
+        "symfony/polyfill-mbstring": "~1.0",
         "symfony/property-access": "~2.3|~3.0.0"
     },
     "require-dev": {
diff --git a/src/Symfony/Component/HttpFoundation/JsonResponse.php b/src/Symfony/Component/HttpFoundation/JsonResponse.php
index 5399d1b1f1..0445a9a6ce 100644
--- a/src/Symfony/Component/HttpFoundation/JsonResponse.php
+++ b/src/Symfony/Component/HttpFoundation/JsonResponse.php
@@ -142,7 +142,7 @@ class JsonResponse extends Response
         }
 
         if (JSON_ERROR_NONE !== json_last_error()) {
-            throw new \InvalidArgumentException($this->transformJsonError());
+            throw new \InvalidArgumentException(json_last_error_msg());
         }
 
         $this->data = $data;
@@ -196,31 +196,4 @@ class JsonResponse extends Response
 
         return $this->setContent($this->data);
     }
-
-    private function transformJsonError()
-    {
-        if (function_exists('json_last_error_msg')) {
-            return json_last_error_msg();
-        }
-
-        switch (json_last_error()) {
-            case JSON_ERROR_DEPTH:
-                return 'Maximum stack depth exceeded.';
-
-            case JSON_ERROR_STATE_MISMATCH:
-                return 'Underflow or the modes mismatch.';
-
-            case JSON_ERROR_CTRL_CHAR:
-                return 'Unexpected control character found.';
-
-            case JSON_ERROR_SYNTAX:
-                return 'Syntax error, malformed JSON.';
-
-            case JSON_ERROR_UTF8:
-                return 'Malformed UTF-8 characters, possibly incorrectly encoded.';
-
-            default:
-                return 'Unknown error.';
-        }
-    }
 }
diff --git a/src/Symfony/Component/HttpFoundation/README.md b/src/Symfony/Component/HttpFoundation/README.md
index 11ad6eef54..a7dba39e0b 100644
--- a/src/Symfony/Component/HttpFoundation/README.md
+++ b/src/Symfony/Component/HttpFoundation/README.md
@@ -34,18 +34,6 @@ $response->send();
 The Request and the Response classes have many other methods that implement
 the HTTP specification.
 
-Loading
--------
-
-If you are not using Composer but are using PHP 5.3.x, you must add the following to your autoloader:
-
-```php
-// SessionHandlerInterface
-if (!interface_exists('SessionHandlerInterface')) {
-    $loader->registerPrefixFallback(__DIR__.'/../vendor/symfony/src/Symfony/Component/HttpFoundation/Resources/stubs');
-}
-```
-
 Resources
 ---------
 
diff --git a/src/Symfony/Component/HttpFoundation/Resources/stubs/SessionHandlerInterface.php b/src/Symfony/Component/HttpFoundation/Resources/stubs/SessionHandlerInterface.php
deleted file mode 100644
index 9baa7bc0f6..0000000000
--- a/src/Symfony/Component/HttpFoundation/Resources/stubs/SessionHandlerInterface.php
+++ /dev/null
@@ -1,102 +0,0 @@
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-/**
- * SessionHandlerInterface for PHP < 5.4.
- *
- * The order in which these methods are invoked by PHP are:
- * 1. open [session_start]
- * 2. read
- * 3. gc [optional depending on probability settings: gc_probability / gc_divisor]
- * 4. destroy [optional when session_regenerate_id(true) is used]
- * 5. write [session_write_close] or destroy [session_destroy]
- * 6. close
- *
- * Extensive documentation can be found at php.net, see links:
- *
- * @see http://php.net/sessionhandlerinterface
- * @see http://php.net/session.customhandler
- * @see http://php.net/session-set-save-handler
- *
- * @author Drak <drak@zikula.org>
- * @author Tobias Schultze <http://tobion.de>
- */
-interface SessionHandlerInterface
-{
-    /**
-     * Re-initializes existing session, or creates a new one.
-     *
-     * @see http://php.net/sessionhandlerinterface.open
-     *
-     * @param string $savePath    Save path
-     * @param string $sessionName Session name, see http://php.net/function.session-name.php
-     *
-     * @return bool true on success, false on failure
-     */
-    public function open($savePath, $sessionName);
-
-    /**
-     * Closes the current session.
-     *
-     * @see http://php.net/sessionhandlerinterface.close
-     *
-     * @return bool true on success, false on failure
-     */
-    public function close();
-
-    /**
-     * Reads the session data.
-     *
-     * @see http://php.net/sessionhandlerinterface.read
-     *
-     * @param string $sessionId Session ID, see http://php.net/function.session-id
-     *
-     * @return string Same session data as passed in write() or empty string when non-existent or on failure
-     */
-    public function read($sessionId);
-
-    /**
-     * Writes the session data to the storage.
-     *
-     * Care, the session ID passed to write() can be different from the one previously
-     * received in read() when the session ID changed due to session_regenerate_id().
-     *
-     * @see http://php.net/sessionhandlerinterface.write
-     *
-     * @param string $sessionId Session ID , see http://php.net/function.session-id
-     * @param string $data      Serialized session data to save
-     *
-     * @return bool true on success, false on failure
-     */
-    public function write($sessionId, $data);
-
-    /**
-     * Destroys a session.
-     *
-     * @see http://php.net/sessionhandlerinterface.destroy
-     *
-     * @param string $sessionId Session ID, see http://php.net/function.session-id
-     *
-     * @return bool true on success, false on failure
-     */
-    public function destroy($sessionId);
-
-    /**
-     * Cleans up expired sessions (garbage collection).
-     *
-     * @see http://php.net/sessionhandlerinterface.gc
-     *
-     * @param string|int $maxlifetime Sessions that have not updated for the last maxlifetime seconds will be removed
-     *
-     * @return bool true on success, false on failure
-     */
-    public function gc($maxlifetime);
-}
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
index fd03dc8447..52e9900d71 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/NativeSessionStorage.php
@@ -101,11 +101,7 @@ class NativeSessionStorage implements SessionStorageInterface
         session_cache_limiter(''); // disable by default because it's managed by HeaderBag (if used)
         ini_set('session.use_cookies', 1);
 
-        if (PHP_VERSION_ID >= 50400) {
-            session_register_shutdown();
-        } else {
-            register_shutdown_function('session_write_close');
-        }
+        session_register_shutdown();
 
         $this->setMetadataBag($metaBag);
         $this->setOptions($options);
diff --git a/src/Symfony/Component/HttpFoundation/composer.json b/src/Symfony/Component/HttpFoundation/composer.json
index 3933c57e73..5a611e6d0c 100644
--- a/src/Symfony/Component/HttpFoundation/composer.json
+++ b/src/Symfony/Component/HttpFoundation/composer.json
@@ -16,14 +16,14 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-php54": "~1.0"
     },
     "require-dev": {
         "symfony/expression-language": "~2.4|~3.0.0"
     },
     "autoload": {
-        "psr-4": { "Symfony\\Component\\HttpFoundation\\": "" },
-        "classmap": [ "Resources/stubs" ]
+        "psr-4": { "Symfony\\Component\\HttpFoundation\\": "" }
     },
     "minimum-stability": "dev",
     "extra": {
diff --git a/src/Symfony/Component/HttpKernel/Tests/Profiler/MongoDbProfilerStorageTest.php b/src/Symfony/Component/HttpKernel/Tests/Profiler/MongoDbProfilerStorageTest.php
index 1e19de10a8..2d093dfd37 100644
--- a/src/Symfony/Component/HttpKernel/Tests/Profiler/MongoDbProfilerStorageTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/Profiler/MongoDbProfilerStorageTest.php
@@ -105,7 +105,7 @@ class MongoDbProfilerStorageTest extends AbstractProfilerStorageTest
         $profile = new Profile('utf8_test_profile');
 
         $data = 'HЁʃʃϿ, ϢorЃd!';
-        $nonUtf8Data = mb_convert_encoding($data, 'UCS-2');
+        $nonUtf8Data = iconv('UTF-8', 'UCS-2', $data);
 
         $collector = new MongoDbProfilerStorageTestDataCollector();
         $collector->setData($nonUtf8Data);
diff --git a/src/Symfony/Component/Intl/Collator/Collator.php b/src/Symfony/Component/Intl/Collator/Collator.php
index 90fba8d491..7482aaa26f 100644
--- a/src/Symfony/Component/Intl/Collator/Collator.php
+++ b/src/Symfony/Component/Intl/Collator/Collator.php
@@ -30,6 +30,8 @@ use Symfony\Component\Intl\Locale\Locale;
  *
  * @author Igor Wiedler <igor@wiedler.ch>
  * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @internal
  */
 class Collator
 {
diff --git a/src/Symfony/Component/Intl/Data/Bundle/Reader/JsonBundleReader.php b/src/Symfony/Component/Intl/Data/Bundle/Reader/JsonBundleReader.php
index 1973843481..84b20abf77 100644
--- a/src/Symfony/Component/Intl/Data/Bundle/Reader/JsonBundleReader.php
+++ b/src/Symfony/Component/Intl/Data/Bundle/Reader/JsonBundleReader.php
@@ -53,37 +53,10 @@ class JsonBundleReader implements BundleReaderInterface
                 'The resource bundle "%s/%s.json" contains invalid JSON: %s',
                 $path,
                 $locale,
-                self::getLastJsonError()
+                json_last_error_msg()
             ));
         }
 
         return $data;
     }
-
-    /**
-     * @return string The last error message created by {@link json_decode()}
-     *
-     * @link http://de2.php.net/manual/en/function.json-last-error-msg.php#113243
-     */
-    private static function getLastJsonError()
-    {
-        if (function_exists('json_last_error_msg')) {
-            return json_last_error_msg();
-        }
-
-        static $errors = array(
-            JSON_ERROR_NONE => null,
-            JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
-            JSON_ERROR_STATE_MISMATCH => 'Underflow or the modes mismatch',
-            JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
-            JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
-            JSON_ERROR_UTF8 => 'Malformed UTF-8 characters, possibly incorrectly encoded',
-        );
-
-        $error = json_last_error();
-
-        return array_key_exists($error, $errors)
-            ? $errors[$error]
-            : sprintf('Unknown error (%s)', $error);
-    }
 }
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
index 0183683932..66376475c6 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/AmPmTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for AM/PM markers format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class AmPmTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
index 6263e22405..a174fdcabc 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfWeekTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for day of week format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class DayOfWeekTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
index 0c88b859d1..5af6dd7243 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayOfYearTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for day of year format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class DayOfYearTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
index 1f79761958..f0ded907c3 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/DayTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for day format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class DayTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/FullTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/FullTransformer.php
index 3c3410e879..0f627d9510 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/FullTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/FullTransformer.php
@@ -18,6 +18,8 @@ use Symfony\Component\Intl\Globals\IntlGlobals;
  * Parser and formatter for date formats.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class FullTransformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
index ce79300267..948e345044 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1200Transformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for 12 hour format (0-11).
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class Hour1200Transformer extends HourTransformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
index 57d0c3192b..19c4d203ab 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour1201Transformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for 12 hour format (1-12).
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class Hour1201Transformer extends HourTransformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
index a6642bc6af..e43d0ee8b2 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2400Transformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for 24 hour format (0-23).
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class Hour2400Transformer extends HourTransformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
index 6fbb445502..df4e671aaf 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Hour2401Transformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for 24 hour format (1-24).
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class Hour2401Transformer extends HourTransformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
index 1dfddefef3..349d8e29ae 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/HourTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Base class for hour transformers.
  *
  * @author Eriksen Costa <eriksen.costa@infranology.com.br>
+ *
+ * @internal
  */
 abstract class HourTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
index ac7b2ae93c..08b5356e3f 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MinuteTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for minute format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class MinuteTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
index 4b02c85b24..6d7c819800 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/MonthTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for month format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class MonthTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
index 944298baf9..fa7e91d038 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/QuarterTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for quarter format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class QuarterTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
index 5d37ed835d..dd2e7bd9f9 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/SecondTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for the second format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class SecondTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimeZoneTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimeZoneTransformer.php
index 6f9c0d5a02..8d16b365e5 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimeZoneTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/TimeZoneTransformer.php
@@ -17,6 +17,8 @@ use Symfony\Component\Intl\Exception\NotImplementedException;
  * Parser and formatter for time zone format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class TimeZoneTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
index 25ecab572a..26a25db355 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/Transformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for date formats.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 abstract class Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php b/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
index a715bf4284..0b546b774a 100644
--- a/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
+++ b/src/Symfony/Component/Intl/DateFormatter/DateFormat/YearTransformer.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\DateFormatter\DateFormat;
  * Parser and formatter for year format.
  *
  * @author Igor Wiedler <igor@wiedler.ch>
+ *
+ * @internal
  */
 class YearTransformer extends Transformer
 {
diff --git a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
index af398afc91..345bd18e18 100644
--- a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
+++ b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
@@ -43,6 +43,8 @@ use Symfony\Component\Intl\Locale\Locale;
  *
  * @author Igor Wiedler <igor@wiedler.ch>
  * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @internal
  */
 class IntlDateFormatter
 {
diff --git a/src/Symfony/Component/Intl/Globals/IntlGlobals.php b/src/Symfony/Component/Intl/Globals/IntlGlobals.php
index 2d5d4d3600..ec2ee17469 100644
--- a/src/Symfony/Component/Intl/Globals/IntlGlobals.php
+++ b/src/Symfony/Component/Intl/Globals/IntlGlobals.php
@@ -15,6 +15,8 @@ namespace Symfony\Component\Intl\Globals;
  * Provides fake static versions of the global functions in the intl extension.
  *
  * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @internal
  */
 abstract class IntlGlobals
 {
diff --git a/src/Symfony/Component/Intl/Locale/Locale.php b/src/Symfony/Component/Intl/Locale/Locale.php
index 23194a064d..0217b14521 100644
--- a/src/Symfony/Component/Intl/Locale/Locale.php
+++ b/src/Symfony/Component/Intl/Locale/Locale.php
@@ -21,6 +21,8 @@ use Symfony\Component\Intl\Exception\MethodNotImplementedException;
  *
  * @author Eriksen Costa <eriksen.costa@infranology.com.br>
  * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @internal
  */
 class Locale
 {
diff --git a/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php b/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
index c1a77a7406..13b1f48868 100644
--- a/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
+++ b/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
@@ -37,6 +37,8 @@ use Symfony\Component\Intl\Locale\Locale;
  *
  * @author Eriksen Costa <eriksen.costa@infranology.com.br>
  * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @internal
  */
 class NumberFormatter
 {
diff --git a/src/Symfony/Component/Intl/Resources/stubs/functions.php b/src/Symfony/Component/Intl/Resources/stubs/functions.php
deleted file mode 100644
index 704f0f0c72..0000000000
--- a/src/Symfony/Component/Intl/Resources/stubs/functions.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-use Symfony\Component\Intl\Globals\IntlGlobals;
-
-if (!function_exists('intl_is_failure')) {
-    /**
-     * Stub implementation for the {@link intl_is_failure()} function of the intl
-     * extension.
-     *
-     * @author Bernhard Schussek <bschussek@gmail.com>
-     *
-     * @param int $errorCode The error code returned by intl_get_error_code().
-     *
-     * @return bool Whether the error code indicates an error.
-     *
-     * @see IntlGlobals::isFailure()
-     */
-    function intl_is_failure($errorCode)
-    {
-        return IntlGlobals::isFailure($errorCode);
-    }
-
-    /**
-     * Stub implementation for the {@link intl_get_error_code()} function of the
-     * intl extension.
-     *
-     * @author Bernhard Schussek <bschussek@gmail.com>
-     *
-     * @return bool The error code of the last intl function call or
-     *              IntlGlobals::U_ZERO_ERROR if no error occurred.
-     *
-     * @see IntlGlobals::getErrorCode()
-     */
-    function intl_get_error_code()
-    {
-        return IntlGlobals::getErrorCode();
-    }
-
-    /**
-     * Stub implementation for the {@link intl_get_error_code()} function of the
-     * intl extension.
-     *
-     * @author Bernhard Schussek <bschussek@gmail.com>
-     *
-     * @return bool The error message of the last intl function call or
-     *              "U_ZERO_ERROR" if no error occurred.
-     *
-     * @see IntlGlobals::getErrorMessage()
-     */
-    function intl_get_error_message()
-    {
-        return IntlGlobals::getErrorMessage();
-    }
-
-    /**
-     * Stub implementation for the {@link intl_error_name()} function of the intl
-     * extension.
-     *
-     * @param int $errorCode The error code.
-     *
-     * @return string The name of the error code constant.
-     *
-     * @see IntlGlobals::getErrorName()
-     */
-    function intl_error_name($errorCode)
-    {
-        return IntlGlobals::getErrorName($errorCode);
-    }
-}
diff --git a/src/Symfony/Component/Intl/composer.json b/src/Symfony/Component/Intl/composer.json
index 2b9a24ebf1..d862424942 100644
--- a/src/Symfony/Component/Intl/composer.json
+++ b/src/Symfony/Component/Intl/composer.json
@@ -24,7 +24,9 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-intl-icu": "~1.0",
+        "symfony/polyfill-php54": "~1.0"
     },
     "require-dev": {
         "symfony/filesystem": "~2.1|~3.0.0"
@@ -34,8 +36,7 @@
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Intl\\": "" },
-        "classmap": [ "Resources/stubs" ],
-        "files": [ "Resources/stubs/functions.php" ]
+        "classmap": [ "Resources/stubs" ]
     },
     "minimum-stability": "dev",
     "extra": {
diff --git a/src/Symfony/Component/Ldap/LdapClient.php b/src/Symfony/Component/Ldap/LdapClient.php
index 41c8892f71..734ff4e906 100644
--- a/src/Symfony/Component/Ldap/LdapClient.php
+++ b/src/Symfony/Component/Ldap/LdapClient.php
@@ -97,11 +97,7 @@ class LdapClient implements LdapClientInterface
      */
     public function escape($subject, $ignore = '', $flags = 0)
     {
-        if (function_exists('ldap_escape')) {
-            return ldap_escape($subject, $ignore, $flags);
-        }
-
-        return $this->doEscape($subject, $ignore, $flags);
+        return ldap_escape($subject, $ignore, $flags);
     }
 
     private function connect()
@@ -132,98 +128,4 @@ class LdapClient implements LdapClientInterface
 
         $this->connection = null;
     }
-
-    /**
-     * Stub implementation of the {@link ldap_escape()} function of the ldap
-     * extension.
-     *
-     * Escape strings for safe use in LDAP filters and DNs.
-     *
-     * @author Chris Wright <ldapi@daverandom.com>
-     *
-     * @param string $subject
-     * @param string $ignore
-     * @param int    $flags
-     *
-     * @return string
-     *
-     * @see http://stackoverflow.com/a/8561604
-     */
-    private function doEscape($subject, $ignore = '', $flags = 0)
-    {
-        $charMaps = $this->getCharmaps();
-
-        // Create the base char map to escape
-        $flags = (int) $flags;
-        $charMap = array();
-
-        if ($flags & self::LDAP_ESCAPE_FILTER) {
-            $charMap += $charMaps[self::LDAP_ESCAPE_FILTER];
-        }
-
-        if ($flags & self::LDAP_ESCAPE_DN) {
-            $charMap += $charMaps[self::LDAP_ESCAPE_DN];
-        }
-
-        if (!$charMap) {
-            $charMap = $charMaps[0];
-        }
-
-        // Remove any chars to ignore from the list
-        $ignore = (string) $ignore;
-
-        for ($i = 0, $l = strlen($ignore); $i < $l; ++$i) {
-            unset($charMap[$ignore[$i]]);
-        }
-
-        // Do the main replacement
-        $result = strtr($subject, $charMap);
-
-        // Encode leading/trailing spaces if LDAP_ESCAPE_DN is passed
-        if ($flags & self::LDAP_ESCAPE_DN) {
-            if ($result[0] === ' ') {
-                $result = '\\20'.substr($result, 1);
-            }
-
-            if ($result[strlen($result) - 1] === ' ') {
-                $result = substr($result, 0, -1).'\\20';
-            }
-        }
-
-        return $result;
-    }
-
-    private function getCharmaps()
-    {
-        if (null !== $this->charmaps) {
-            return $this->charmaps;
-        }
-
-        $charMaps = array(
-            self::LDAP_ESCAPE_FILTER => array('\\', '*', '(', ')', "\x00"),
-            self::LDAP_ESCAPE_DN => array('\\', ',', '=', '+', '<', '>', ';', '"', '#'),
-        );
-
-        $charMaps[0] = array();
-
-        for ($i = 0; $i < 256; ++$i) {
-            $charMaps[0][chr($i)] = sprintf('\\%02x', $i);
-        }
-
-        for ($i = 0, $l = count($charMaps[self::LDAP_ESCAPE_FILTER]); $i < $l; ++$i) {
-            $chr = $charMaps[self::LDAP_ESCAPE_FILTER][$i];
-            unset($charMaps[self::LDAP_ESCAPE_FILTER][$i]);
-            $charMaps[self::LDAP_ESCAPE_FILTER][$chr] = $charMaps[0][$chr];
-        }
-
-        for ($i = 0, $l = count($charMaps[self::LDAP_ESCAPE_DN]); $i < $l; ++$i) {
-            $chr = $charMaps[self::LDAP_ESCAPE_DN][$i];
-            unset($charMaps[self::LDAP_ESCAPE_DN][$i]);
-            $charMaps[self::LDAP_ESCAPE_DN][$chr] = $charMaps[0][$chr];
-        }
-
-        $this->charmaps = $charMaps;
-
-        return $this->charmaps;
-    }
 }
diff --git a/src/Symfony/Component/Ldap/Tests/LdapClientTest.php b/src/Symfony/Component/Ldap/Tests/LdapClientTest.php
deleted file mode 100644
index 22a548c272..0000000000
--- a/src/Symfony/Component/Ldap/Tests/LdapClientTest.php
+++ /dev/null
@@ -1,52 +0,0 @@
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace Symfony\Component\Security\Core\Tests\Authentication\Provider;
-
-use Symfony\Component\Ldap\LdapClient;
-
-/**
- * @requires extension ldap
- */
-class LdapClientTest extends \PHPUnit_Framework_TestCase
-{
-    /**
-     * @dataProvider provideLdapEscapeValues
-     */
-    public function testLdapEscape($subject, $ignore, $flags, $expected)
-    {
-        $ldap = new LdapClient();
-        $this->assertSame($expected, $ldap->escape($subject, $ignore, $flags));
-    }
-
-    /**
-     * Provides values for the ldap_escape shim. These tests come from the official
-     * extension.
-     *
-     * @see https://github.com/php/php-src/blob/master/ext/ldap/tests/ldap_escape_dn.phpt
-     * @see https://github.com/php/php-src/blob/master/ext/ldap/tests/ldap_escape_all.phpt
-     * @see https://github.com/php/php-src/blob/master/ext/ldap/tests/ldap_escape_both.phpt
-     * @see https://github.com/php/php-src/blob/master/ext/ldap/tests/ldap_escape_filter.phpt
-     * @see https://github.com/php/php-src/blob/master/ext/ldap/tests/ldap_escape_ignore.phpt
-     *
-     * @return array
-     */
-    public function provideLdapEscapeValues()
-    {
-        return array(
-            array('foo=bar(baz)*', null, LdapClient::LDAP_ESCAPE_DN, 'foo\3dbar(baz)*'),
-            array('foo=bar(baz)*', null, null, '\66\6f\6f\3d\62\61\72\28\62\61\7a\29\2a'),
-            array('foo=bar(baz)*', null, LdapClient::LDAP_ESCAPE_DN | LdapClient::LDAP_ESCAPE_FILTER, 'foo\3dbar\28baz\29\2a'),
-            array('foo=bar(baz)*', null, LdapClient::LDAP_ESCAPE_FILTER, 'foo=bar\28baz\29\2a'),
-            array('foo=bar(baz)*', 'ao', null, '\66oo\3d\62a\72\28\62a\7a\29\2a'),
-        );
-    }
-}
diff --git a/src/Symfony/Component/Ldap/composer.json b/src/Symfony/Component/Ldap/composer.json
index 612b7c83fe..21e4adea96 100644
--- a/src/Symfony/Component/Ldap/composer.json
+++ b/src/Symfony/Component/Ldap/composer.json
@@ -17,6 +17,7 @@
     ],
     "require": {
         "php": ">=5.3.9",
+        "symfony/polyfill-php56": "~1.0",
         "ext-ldap": "*"
     },
     "autoload": {
diff --git a/src/Symfony/Component/Security/Core/Encoder/BCryptPasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/BCryptPasswordEncoder.php
index d2b031999c..c0c8fe0993 100644
--- a/src/Symfony/Component/Security/Core/Encoder/BCryptPasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/BCryptPasswordEncoder.php
@@ -34,10 +34,6 @@ class BCryptPasswordEncoder extends BasePasswordEncoder
      */
     public function __construct($cost)
     {
-        if (!function_exists('password_hash')) {
-            throw new \RuntimeException('To use the BCrypt encoder, you need to upgrade to PHP 5.5 or install the "ircmaxell/password-compat" via Composer.');
-        }
-
         $cost = (int) $cost;
         if ($cost < 4 || $cost > 31) {
             throw new \InvalidArgumentException('Cost must be in the range of 4-31.');
diff --git a/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
index 1c9ada1e64..12126d8454 100644
--- a/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/BasePasswordEncoder.php
@@ -11,8 +11,6 @@
 
 namespace Symfony\Component\Security\Core\Encoder;
 
-use Symfony\Component\Security\Core\Util\StringUtils;
-
 /**
  * BasePasswordEncoder is the base class for all password encoders.
  *
@@ -83,7 +81,7 @@ abstract class BasePasswordEncoder implements PasswordEncoderInterface
      */
     protected function comparePasswords($password1, $password2)
     {
-        return StringUtils::equals($password1, $password2);
+        return hash_equals($password1, $password2);
     }
 
     /**
diff --git a/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php b/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
index 6f24c4f1e2..8422a4baae 100644
--- a/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
+++ b/src/Symfony/Component/Security/Core/Encoder/Pbkdf2PasswordEncoder.php
@@ -64,11 +64,7 @@ class Pbkdf2PasswordEncoder extends BasePasswordEncoder
             throw new \LogicException(sprintf('The algorithm "%s" is not supported.', $this->algorithm));
         }
 
-        if (function_exists('hash_pbkdf2')) {
-            $digest = hash_pbkdf2($this->algorithm, $raw, $salt, $this->iterations, $this->length, true);
-        } else {
-            $digest = $this->hashPbkdf2($this->algorithm, $raw, $salt, $this->iterations, $this->length);
-        }
+        $digest = hash_pbkdf2($this->algorithm, $raw, $salt, $this->iterations, $this->length, true);
 
         return $this->encodeHashAsBase64 ? base64_encode($digest) : bin2hex($digest);
     }
@@ -80,24 +76,4 @@ class Pbkdf2PasswordEncoder extends BasePasswordEncoder
     {
         return !$this->isPasswordTooLong($raw) && $this->comparePasswords($encoded, $this->encodePassword($raw, $salt));
     }
-
-    private function hashPbkdf2($algorithm, $password, $salt, $iterations, $length = 0)
-    {
-        // Number of blocks needed to create the derived key
-        $blocks = ceil($length / strlen(hash($algorithm, null, true)));
-        $digest = '';
-
-        for ($i = 1; $i <= $blocks; ++$i) {
-            $ib = $block = hash_hmac($algorithm, $salt.pack('N', $i), $password, true);
-
-            // Iterations
-            for ($j = 1; $j < $iterations; ++$j) {
-                $ib ^= ($block = hash_hmac($algorithm, $block, $password, true));
-            }
-
-            $digest .= $ib;
-        }
-
-        return substr($digest, 0, $this->length);
-    }
 }
diff --git a/src/Symfony/Component/Security/Core/Tests/Util/StringUtilsTest.php b/src/Symfony/Component/Security/Core/Tests/Util/StringUtilsTest.php
index faeaf259f7..78d9b05a17 100644
--- a/src/Symfony/Component/Security/Core/Tests/Util/StringUtilsTest.php
+++ b/src/Symfony/Component/Security/Core/Tests/Util/StringUtilsTest.php
@@ -15,6 +15,8 @@ use Symfony\Component\Security\Core\Util\StringUtils;
 
 /**
  * Data from PHP.net's hash_equals tests.
+ *
+ * @group legacy
  */
 class StringUtilsTest extends \PHPUnit_Framework_TestCase
 {
diff --git a/src/Symfony/Component/Security/Core/Util/StringUtils.php b/src/Symfony/Component/Security/Core/Util/StringUtils.php
index 343585c88c..5900812f92 100644
--- a/src/Symfony/Component/Security/Core/Util/StringUtils.php
+++ b/src/Symfony/Component/Security/Core/Util/StringUtils.php
@@ -11,10 +11,16 @@
 
 namespace Symfony\Component\Security\Core\Util;
 
+@trigger_error('The '.__NAMESPACE__.'\\StringUtils class is deprecated since version 2.8 and will be removed in 3.0. Use hash_equals() instead.', E_USER_DEPRECATED);
+
+use Symfony\Component\Polyfill\Util\Binary;
+
 /**
  * String utility functions.
  *
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @deprecated since 2.8, to be removed in 3.0.
  */
 class StringUtils
 {
@@ -47,25 +53,7 @@ class StringUtils
             $userInput = (string) $userInput;
         }
 
-        if (function_exists('hash_equals')) {
-            return hash_equals($knownString, $userInput);
-        }
-
-        $knownLen = self::safeStrlen($knownString);
-        $userLen = self::safeStrlen($userInput);
-
-        if ($userLen !== $knownLen) {
-            return false;
-        }
-
-        $result = 0;
-
-        for ($i = 0; $i < $knownLen; ++$i) {
-            $result |= (ord($knownString[$i]) ^ ord($userInput[$i]));
-        }
-
-        // They are only identical strings if $result is exactly 0...
-        return 0 === $result;
+        return hash_equals($knownString, $userInput);
     }
 
     /**
@@ -77,17 +65,6 @@ class StringUtils
      */
     public static function safeStrlen($string)
     {
-        // Premature optimization
-        // Since this cannot be changed at runtime, we can cache it
-        static $funcExists = null;
-        if (null === $funcExists) {
-            $funcExists = function_exists('mb_strlen');
-        }
-
-        if ($funcExists) {
-            return mb_strlen($string, '8bit');
-        }
-
-        return strlen($string);
+        return Binary::strlen($string);
     }
 }
diff --git a/src/Symfony/Component/Security/Core/composer.json b/src/Symfony/Component/Security/Core/composer.json
index 31b4653967..c75d2d5fce 100644
--- a/src/Symfony/Component/Security/Core/composer.json
+++ b/src/Symfony/Component/Security/Core/composer.json
@@ -17,25 +17,25 @@
     ],
     "require": {
         "php": ">=5.3.9",
-        "paragonie/random_compat": "~1.0"
+        "symfony/polyfill-php55": "~1.0",
+        "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-util": "~1.0"
     },
     "require-dev": {
         "symfony/event-dispatcher": "~2.1|~3.0.0",
         "symfony/expression-language": "~2.6|~3.0.0",
         "symfony/http-foundation": "~2.4|~3.0.0",
+        "symfony/ldap": "~2.8|~3.0.0",
         "symfony/translation": "~2.0,>=2.0.5|~3.0.0",
         "symfony/validator": "~2.5,>=2.5.5|~3.0.0",
-        "psr/log": "~1.0",
-        "ircmaxell/password-compat": "1.0.*",
-        "symfony/ldap": "~2.8|~3.0.0"
+        "psr/log": "~1.0"
     },
     "suggest": {
         "symfony/event-dispatcher": "",
         "symfony/http-foundation": "",
         "symfony/validator": "For using the user password constraint",
         "symfony/expression-language": "For using the expression voter",
-        "symfony/ldap": "For using LDAP integration",
-        "ircmaxell/password-compat": "For using the BCrypt password encoder in PHP <5.5"
+        "symfony/ldap": "For using LDAP integration"
     },
     "autoload": {
         "psr-4": { "Symfony\\Component\\Security\\Core\\": "" }
diff --git a/src/Symfony/Component/Security/Csrf/CsrfTokenManager.php b/src/Symfony/Component/Security/Csrf/CsrfTokenManager.php
index e1295029ac..cdda543cc0 100644
--- a/src/Symfony/Component/Security/Csrf/CsrfTokenManager.php
+++ b/src/Symfony/Component/Security/Csrf/CsrfTokenManager.php
@@ -11,7 +11,6 @@
 
 namespace Symfony\Component\Security\Csrf;
 
-use Symfony\Component\Security\Core\Util\StringUtils;
 use Symfony\Component\Security\Csrf\TokenGenerator\UriSafeTokenGenerator;
 use Symfony\Component\Security\Csrf\TokenGenerator\TokenGeneratorInterface;
 use Symfony\Component\Security\Csrf\TokenStorage\NativeSessionTokenStorage;
@@ -92,6 +91,6 @@ class CsrfTokenManager implements CsrfTokenManagerInterface
             return false;
         }
 
-        return StringUtils::equals($this->storage->getToken($token->getId()), $token->getValue());
+        return hash_equals($this->storage->getToken($token->getId()), $token->getValue());
     }
 }
diff --git a/src/Symfony/Component/Security/Csrf/composer.json b/src/Symfony/Component/Security/Csrf/composer.json
index 2afebf913f..c8e2fae319 100644
--- a/src/Symfony/Component/Security/Csrf/composer.json
+++ b/src/Symfony/Component/Security/Csrf/composer.json
@@ -17,8 +17,8 @@
     ],
     "require": {
         "php": ">=5.3.9",
-        "symfony/security-core": "~2.4|~3.0.0",
-        "paragonie/random_compat": "~1.0"
+        "symfony/polyfill-php56": "~1.0",
+        "symfony/security-core": "~2.4|~3.0.0"
     },
     "require-dev": {
         "symfony/http-foundation": "~2.1|~3.0.0"
diff --git a/src/Symfony/Component/Security/Http/RememberMe/TokenBasedRememberMeServices.php b/src/Symfony/Component/Security/Http/RememberMe/TokenBasedRememberMeServices.php
index f6107ec406..a4437027d0 100644
--- a/src/Symfony/Component/Security/Http/RememberMe/TokenBasedRememberMeServices.php
+++ b/src/Symfony/Component/Security/Http/RememberMe/TokenBasedRememberMeServices.php
@@ -17,7 +17,6 @@ use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
 use Symfony\Component\Security\Core\Exception\AuthenticationException;
 use Symfony\Component\Security\Core\User\UserInterface;
-use Symfony\Component\Security\Core\Util\StringUtils;
 
 /**
  * Concrete implementation of the RememberMeServicesInterface providing
@@ -54,7 +53,7 @@ class TokenBasedRememberMeServices extends AbstractRememberMeServices
             throw new \RuntimeException(sprintf('The UserProviderInterface implementation must return an instance of UserInterface, but returned "%s".', get_class($user)));
         }
 
-        if (true !== StringUtils::equals($this->generateCookieHash($class, $username, $expires, $user->getPassword()), $hash)) {
+        if (true !== hash_equals($this->generateCookieHash($class, $username, $expires, $user->getPassword()), $hash)) {
             throw new AuthenticationException('The cookie\'s hash is invalid.');
         }
 
diff --git a/src/Symfony/Component/Security/Http/composer.json b/src/Symfony/Component/Security/Http/composer.json
index 65978ee107..686a629e74 100644
--- a/src/Symfony/Component/Security/Http/composer.json
+++ b/src/Symfony/Component/Security/Http/composer.json
@@ -21,8 +21,9 @@
         "symfony/event-dispatcher": "~2.1|~3.0.0",
         "symfony/http-foundation": "~2.4|~3.0.0",
         "symfony/http-kernel": "~2.4|~3.0.0",
-        "symfony/property-access": "~2.3|~3.0.0",
-        "paragonie/random_compat": "~1.0"
+        "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-php70": "~1.0",
+        "symfony/property-access": "~2.3|~3.0.0"
     },
     "require-dev": {
         "symfony/routing": "~2.2|~3.0.0",
diff --git a/src/Symfony/Component/Security/composer.json b/src/Symfony/Component/Security/composer.json
index 65a2eb0bc6..beb2f88c52 100644
--- a/src/Symfony/Component/Security/composer.json
+++ b/src/Symfony/Component/Security/composer.json
@@ -21,8 +21,11 @@
         "symfony/event-dispatcher": "~2.2|~3.0.0",
         "symfony/http-foundation": "~2.1|~3.0.0",
         "symfony/http-kernel": "~2.4|~3.0.0",
-        "symfony/property-access": "~2.3|~3.0.0",
-        "paragonie/random_compat": "~1.0"
+        "symfony/polyfill-php55": "~1.0",
+        "symfony/polyfill-php56": "~1.0",
+        "symfony/polyfill-php70": "~1.0",
+        "symfony/polyfill-util": "~1.0",
+        "symfony/property-access": "~2.3|~3.0.0"
     },
     "replace": {
         "symfony/security-core": "self.version",
@@ -32,14 +35,13 @@
     },
     "require-dev": {
         "symfony/finder": "~2.3|~3.0.0",
-        "symfony/intl": "~2.3|~3.0.0",
+        "symfony/polyfill-intl-icu": "~1.0",
         "symfony/routing": "~2.2|~3.0.0",
         "symfony/translation": "~2.0,>=2.0.5|~3.0.0",
         "symfony/validator": "~2.5,>=2.5.5|~3.0.0",
         "doctrine/common": "~2.2",
         "doctrine/dbal": "~2.2",
         "psr/log": "~1.0",
-        "ircmaxell/password-compat": "~1.0",
         "symfony/expression-language": "~2.6|~3.0.0",
         "symfony/ldap": "~2.8|~3.0.0"
     },
@@ -50,7 +52,6 @@
         "symfony/validator": "For using the user password constraint",
         "symfony/routing": "For using the HttpUtils class to create sub-requests, redirect the user, and match URLs",
         "symfony/expression-language": "For using the expression voter",
-        "ircmaxell/password-compat": "For using the BCrypt password encoder in PHP <5.5",
         "symfony/ldap": "For using the LDAP user and authentication providers"
     },
     "autoload": {
diff --git a/src/Symfony/Component/Serializer/Encoder/JsonDecode.php b/src/Symfony/Component/Serializer/Encoder/JsonDecode.php
index 5f5f2899f5..d4070c2304 100644
--- a/src/Symfony/Component/Serializer/Encoder/JsonDecode.php
+++ b/src/Symfony/Component/Serializer/Encoder/JsonDecode.php
@@ -108,7 +108,7 @@ class JsonDecode implements DecoderInterface
         }
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(JsonEncoder::getLastErrorMessage());
+            throw new UnexpectedValueException(json_last_error_message());
         }
 
         return $decodedData;
diff --git a/src/Symfony/Component/Serializer/Encoder/JsonEncode.php b/src/Symfony/Component/Serializer/Encoder/JsonEncode.php
index 3a6b2fdbbb..aa7d64530e 100644
--- a/src/Symfony/Component/Serializer/Encoder/JsonEncode.php
+++ b/src/Symfony/Component/Serializer/Encoder/JsonEncode.php
@@ -56,7 +56,7 @@ class JsonEncode implements EncoderInterface
         $encodedJson = json_encode($data, $context['json_encode_options']);
 
         if (JSON_ERROR_NONE !== $this->lastError = json_last_error()) {
-            throw new UnexpectedValueException(JsonEncoder::getLastErrorMessage());
+            throw new UnexpectedValueException(json_last_error_message());
         }
 
         return $encodedJson;
diff --git a/src/Symfony/Component/Serializer/Encoder/JsonEncoder.php b/src/Symfony/Component/Serializer/Encoder/JsonEncoder.php
index 284f579a04..159d435836 100644
--- a/src/Symfony/Component/Serializer/Encoder/JsonEncoder.php
+++ b/src/Symfony/Component/Serializer/Encoder/JsonEncoder.php
@@ -100,26 +100,13 @@ class JsonEncoder implements EncoderInterface, DecoderInterface
      * Resolves json_last_error message.
      *
      * @return string
+     *
+     * @deprecated since 2.8, to be removed in 3.0. Use json_last_error_msg() instead.
      */
     public static function getLastErrorMessage()
     {
-        if (function_exists('json_last_error_msg')) {
-            return json_last_error_msg();
-        }
+        @trigger_error('The '.__METHOD__.' method is deprecated since version 2.8 and will be removed in 3.0. Use json_last_error_msg() instead.', E_USER_DEPRECATED);
 
-        switch (json_last_error()) {
-            case JSON_ERROR_DEPTH:
-                return 'Maximum stack depth exceeded';
-            case JSON_ERROR_STATE_MISMATCH:
-                return 'Underflow or the modes mismatch';
-            case JSON_ERROR_CTRL_CHAR:
-                return 'Unexpected control character found';
-            case JSON_ERROR_SYNTAX:
-                return 'Syntax error, malformed JSON';
-            case JSON_ERROR_UTF8:
-                return 'Malformed UTF-8 characters, possibly incorrectly encoded';
-            default:
-                return 'Unknown error';
-        }
+        return json_last_error_msg();
     }
 }
diff --git a/src/Symfony/Component/Serializer/composer.json b/src/Symfony/Component/Serializer/composer.json
index 58783fff10..8872215af0 100644
--- a/src/Symfony/Component/Serializer/composer.json
+++ b/src/Symfony/Component/Serializer/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-php54": "~1.0"
     },
     "require-dev": {
         "symfony/yaml": "~2.0,>=2.0.5|~3.0.0",
diff --git a/src/Symfony/Component/Templating/PhpEngine.php b/src/Symfony/Component/Templating/PhpEngine.php
index 253796c051..042dc6c8e9 100644
--- a/src/Symfony/Component/Templating/PhpEngine.php
+++ b/src/Symfony/Component/Templating/PhpEngine.php
@@ -330,6 +330,9 @@ class PhpEngine implements EngineInterface, \ArrayAccess
      */
     public function setCharset($charset)
     {
+        if ('UTF8' === $charset = strtoupper($charset)) {
+            $charset = 'UTF-8'; // iconv on Windows requires "UTF-8" instead of "UTF8"
+        }
         $this->charset = $charset;
 
         foreach ($this->helpers as $helper) {
@@ -448,7 +451,7 @@ class PhpEngine implements EngineInterface, \ArrayAccess
                  */
                 function ($value) use ($that) {
                     if ('UTF-8' != $that->getCharset()) {
-                        $value = $that->convertEncoding($value, 'UTF-8', $that->getCharset());
+                        $value = iconv($that->getCharset(), 'UTF-8', $value);
                     }
 
                     $callback = function ($matches) use ($that) {
@@ -460,7 +463,7 @@ class PhpEngine implements EngineInterface, \ArrayAccess
                         }
 
                         // \uHHHH
-                        $char = $that->convertEncoding($char, 'UTF-16BE', 'UTF-8');
+                        $char = iconv('UTF-8', 'UTF-16BE', $char);
 
                         return '\\u'.substr('0000'.bin2hex($char), -4);
                     };
@@ -470,7 +473,7 @@ class PhpEngine implements EngineInterface, \ArrayAccess
                     }
 
                     if ('UTF-8' != $that->getCharset()) {
-                        $value = $that->convertEncoding($value, $that->getCharset(), 'UTF-8');
+                        $value = iconv('UTF-8', $that->getCharset(), $value);
                     }
 
                     return $value;
@@ -489,17 +492,13 @@ class PhpEngine implements EngineInterface, \ArrayAccess
      *
      * @return string The string with the new encoding
      *
-     * @throws \RuntimeException if no suitable encoding function is found (iconv or mbstring)
+     * @deprecated since 2.8, to be removed in 3.0. Use iconv() instead.
      */
     public function convertEncoding($string, $to, $from)
     {
-        if (function_exists('mb_convert_encoding')) {
-            return mb_convert_encoding($string, $to, $from);
-        } elseif (function_exists('iconv')) {
-            return iconv($from, $to, $string);
-        }
+        @trigger_error('The '.__METHOD__.' method is deprecated since version 2.8 and will be removed in 3.0. Use iconv() instead.', E_USER_DEPRECATED);
 
-        throw new \RuntimeException('No suitable convert encoding function (use UTF-8 as your encoding or install the iconv or mbstring extension).');
+        return iconv($from, $to, $string);
     }
 
     /**
diff --git a/src/Symfony/Component/Translation/DataCollector/TranslationDataCollector.php b/src/Symfony/Component/Translation/DataCollector/TranslationDataCollector.php
index 090f16d7ec..cb59d0a7e7 100644
--- a/src/Symfony/Component/Translation/DataCollector/TranslationDataCollector.php
+++ b/src/Symfony/Component/Translation/DataCollector/TranslationDataCollector.php
@@ -137,7 +137,7 @@ class TranslationDataCollector extends DataCollector implements LateDataCollecto
     {
         $string = trim(preg_replace('/\s+/', ' ', $string));
 
-        if (function_exists('mb_strlen') && false !== $encoding = mb_detect_encoding($string)) {
+        if (false !== $encoding = mb_detect_encoding($string, null, true)) {
             if (mb_strlen($string, $encoding) > $length) {
                 return mb_substr($string, 0, $length - 3, $encoding).'...';
             }
diff --git a/src/Symfony/Component/Translation/Loader/XliffFileLoader.php b/src/Symfony/Component/Translation/Loader/XliffFileLoader.php
index 3f95b42b00..bdca11099d 100644
--- a/src/Symfony/Component/Translation/Loader/XliffFileLoader.php
+++ b/src/Symfony/Component/Translation/Loader/XliffFileLoader.php
@@ -153,15 +153,7 @@ class XliffFileLoader implements LoaderInterface
     private function utf8ToCharset($content, $encoding = null)
     {
         if ('UTF-8' !== $encoding && !empty($encoding)) {
-            if (function_exists('mb_convert_encoding')) {
-                return mb_convert_encoding($content, $encoding, 'UTF-8');
-            }
-
-            if (function_exists('iconv')) {
-                return iconv('UTF-8', $encoding, $content);
-            }
-
-            throw new \RuntimeException('No suitable convert encoding function (use UTF-8 as your encoding or install the iconv or mbstring extension).');
+            return mb_convert_encoding($content, $encoding, 'UTF-8');
         }
 
         return $content;
diff --git a/src/Symfony/Component/Translation/Tests/Dumper/IcuResFileDumperTest.php b/src/Symfony/Component/Translation/Tests/Dumper/IcuResFileDumperTest.php
index 117218aec7..618783c04c 100644
--- a/src/Symfony/Component/Translation/Tests/Dumper/IcuResFileDumperTest.php
+++ b/src/Symfony/Component/Translation/Tests/Dumper/IcuResFileDumperTest.php
@@ -16,9 +16,6 @@ use Symfony\Component\Translation\Dumper\IcuResFileDumper;
 
 class IcuResFileDumperTest extends \PHPUnit_Framework_TestCase
 {
-    /**
-     * @requires extension mbstring
-     */
     public function testFormatCatalogue()
     {
         $catalogue = new MessageCatalogue('en');
diff --git a/src/Symfony/Component/Translation/Tests/Loader/XliffFileLoaderTest.php b/src/Symfony/Component/Translation/Tests/Loader/XliffFileLoaderTest.php
index 8f8224a5cb..01e64c3973 100644
--- a/src/Symfony/Component/Translation/Tests/Loader/XliffFileLoaderTest.php
+++ b/src/Symfony/Component/Translation/Tests/Loader/XliffFileLoaderTest.php
@@ -59,9 +59,6 @@ class XliffFileLoaderTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(array('foo' => 'bar', 'extra' => 'extra', 'key' => '', 'test' => 'with'), $catalogue->all('domain1'));
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testEncoding()
     {
         $loader = new XliffFileLoader();
diff --git a/src/Symfony/Component/Translation/composer.json b/src/Symfony/Component/Translation/composer.json
index 71a7450002..07f2b9d10f 100644
--- a/src/Symfony/Component/Translation/composer.json
+++ b/src/Symfony/Component/Translation/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
         "symfony/config": "~2.8",
diff --git a/src/Symfony/Component/Validator/Constraints/LengthValidator.php b/src/Symfony/Component/Validator/Constraints/LengthValidator.php
index 7ef9f269d0..97374953e1 100644
--- a/src/Symfony/Component/Validator/Constraints/LengthValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/LengthValidator.php
@@ -42,29 +42,11 @@ class LengthValidator extends ConstraintValidator
         $invalidCharset = false;
 
         if ('UTF8' === $charset = strtoupper($constraint->charset)) {
-            $charset = 'UTF-8';
+            $charset = 'UTF-8'; // iconv on Windows requires "UTF-8" instead of "UTF8"
         }
 
-        if ('UTF-8' === $charset) {
-            if (!preg_match('//u', $stringValue)) {
-                $invalidCharset = true;
-            } elseif (function_exists('utf8_decode')) {
-                $length = strlen(utf8_decode($stringValue));
-            } else {
-                preg_replace('/./u', '', $stringValue, -1, $length);
-            }
-        } elseif (function_exists('mb_strlen')) {
-            if (@mb_check_encoding($stringValue, $constraint->charset)) {
-                $length = mb_strlen($stringValue, $constraint->charset);
-            } else {
-                $invalidCharset = true;
-            }
-        } elseif (function_exists('iconv_strlen')) {
-            $length = @iconv_strlen($stringValue, $constraint->charset);
-            $invalidCharset = false === $length;
-        } else {
-            $length = strlen($stringValue);
-        }
+        $length = @iconv_strlen($stringValue, $charset);
+        $invalidCharset = false === $length;
 
         if ($invalidCharset) {
             if ($this->context instanceof ExecutionContextInterface) {
diff --git a/src/Symfony/Component/Validator/Tests/Constraints/LengthValidatorTest.php b/src/Symfony/Component/Validator/Tests/Constraints/LengthValidatorTest.php
index b94fdae95c..cd501819d9 100644
--- a/src/Symfony/Component/Validator/Tests/Constraints/LengthValidatorTest.php
+++ b/src/Symfony/Component/Validator/Tests/Constraints/LengthValidatorTest.php
@@ -87,9 +87,6 @@ class LengthValidatorTest extends AbstractConstraintValidatorTest
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function getOneCharset()
     {
         return array(
diff --git a/src/Symfony/Component/VarDumper/Caster/CutStub.php b/src/Symfony/Component/VarDumper/Caster/CutStub.php
index 244829c5ba..8781f5cf3c 100644
--- a/src/Symfony/Component/VarDumper/Caster/CutStub.php
+++ b/src/Symfony/Component/VarDumper/Caster/CutStub.php
@@ -48,7 +48,7 @@ class CutStub extends Stub
             case 'string':
                 $this->type = self::TYPE_STRING;
                 $this->class = preg_match('//u', $value) ? self::STRING_UTF8 : self::STRING_BINARY;
-                $this->cut = self::STRING_BINARY === $this->class ? strlen($value) : (function_exists('iconv_strlen') ? iconv_strlen($value, 'UTF-8') : -1);
+                $this->cut = self::STRING_BINARY === $this->class ? strlen($value) : mb_strlen($value, 'UTF-8');
                 $this->value = '';
                 break;
         }
diff --git a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
index a63af92acd..9e298c429c 100644
--- a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
+++ b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
@@ -185,9 +185,6 @@ abstract class AbstractCloner implements ClonerInterface
         $this->filter = $filter;
         $this->prevErrorHandler = set_error_handler(array($this, 'handleError'));
         try {
-            if (!function_exists('iconv')) {
-                $this->maxString = -1;
-            }
             $data = $this->doClone($var);
         } catch (\Exception $e) {
         }
diff --git a/src/Symfony/Component/VarDumper/Dumper/AbstractDumper.php b/src/Symfony/Component/VarDumper/Dumper/AbstractDumper.php
index cc4b2ef498..f8b9c10777 100644
--- a/src/Symfony/Component/VarDumper/Dumper/AbstractDumper.php
+++ b/src/Symfony/Component/VarDumper/Dumper/AbstractDumper.php
@@ -30,7 +30,6 @@ abstract class AbstractDumper implements DataDumperInterface, DumperInterface
     protected $indentPad = '  ';
 
     private $charset;
-    private $charsetConverter;
 
     /**
      * @param callable|resource|string|null $output  A line dumper callable, an opened stream or an output path, defaults to static::$defaultOutput.
@@ -82,29 +81,11 @@ abstract class AbstractDumper implements DataDumperInterface, DumperInterface
     public function setCharset($charset)
     {
         $prev = $this->charset;
-        $this->charsetConverter = 'fallback';
 
         $charset = strtoupper($charset);
         $charset = null === $charset || 'UTF-8' === $charset || 'UTF8' === $charset ? 'CP1252' : $charset;
 
-        $supported = true;
-        set_error_handler(function () use (&$supported) {$supported = false;});
-
-        if (function_exists('mb_encoding_aliases') && mb_encoding_aliases($charset)) {
-            $this->charset = $charset;
-            $this->charsetConverter = 'mbstring';
-        } elseif (function_exists('iconv')) {
-            $supported = true;
-            iconv($charset, 'UTF-8', '');
-            if ($supported) {
-                $this->charset = $charset;
-                $this->charsetConverter = 'iconv';
-            }
-        }
-        if ('fallback' === $this->charsetConverter) {
-            $this->charset = 'ISO-8859-1';
-        }
-        restore_error_handler();
+        $this->charset = $charset;
 
         return $prev;
     }
@@ -183,40 +164,13 @@ abstract class AbstractDumper implements DataDumperInterface, DumperInterface
      */
     protected function utf8Encode($s)
     {
-        if ('mbstring' === $this->charsetConverter) {
-            return mb_convert_encoding($s, 'UTF-8', mb_check_encoding($s, $this->charset) ? $this->charset : '8bit');
+        if (false !== $c = @iconv($this->charset, 'UTF-8', $s)) {
+            return $c;
         }
-        if ('iconv' === $this->charsetConverter) {
-            $valid = true;
-            set_error_handler(function () use (&$valid) {$valid = false;});
-            $c = iconv($this->charset, 'UTF-8', $s);
-            restore_error_handler();
-            if ($valid) {
-                return $c;
-            }
+        if ('CP1252' !== $this->charset && false !== $c = @iconv('CP1252', 'UTF-8', $s)) {
+            return $c;
         }
 
-        $s .= $s;
-        $len = strlen($s);
-
-        for ($i = $len >> 1, $j = 0; $i < $len; ++$i, ++$j) {
-            switch (true) {
-                case $s[$i] < "\x80":
-                    $s[$j] = $s[$i];
-                    break;
-
-                case $s[$i] < "\xC0":
-                    $s[$j] = "\xC2";
-                    $s[++$j] = $s[$i];
-                    break;
-
-                default:
-                    $s[$j] = "\xC3";
-                    $s[++$j] = chr(ord($s[$i]) - 64);
-                    break;
-            }
-        }
-
-        return substr($s, 0, $j);
+        return iconv('CP850', 'UTF-8', $s);
     }
 }
diff --git a/src/Symfony/Component/VarDumper/Dumper/CliDumper.php b/src/Symfony/Component/VarDumper/Dumper/CliDumper.php
index 37e4110abe..bca2abcb3d 100644
--- a/src/Symfony/Component/VarDumper/Dumper/CliDumper.php
+++ b/src/Symfony/Component/VarDumper/Dumper/CliDumper.php
@@ -91,9 +91,7 @@ class CliDumper extends AbstractDumper
      */
     public function setMaxStringWidth($maxStringWidth)
     {
-        if (function_exists('iconv')) {
-            $this->maxStringWidth = (int) $maxStringWidth;
-        }
+        $this->maxStringWidth = (int) $maxStringWidth;
     }
 
     /**
@@ -171,7 +169,7 @@ class CliDumper extends AbstractDumper
             $this->dumpLine($cursor->depth, true);
         } else {
             $attr = array(
-                'length' => 0 <= $cut && function_exists('iconv_strlen') ? iconv_strlen($str, 'UTF-8') + $cut : 0,
+                'length' => 0 <= $cut ? iconv_strlen($str, 'UTF-8') + $cut : 0,
                 'binary' => $bin,
             );
             $str = explode("\n", $str);
diff --git a/src/Symfony/Component/VarDumper/Dumper/HtmlDumper.php b/src/Symfony/Component/VarDumper/Dumper/HtmlDumper.php
index 0ae752166a..28af8e4cb2 100644
--- a/src/Symfony/Component/VarDumper/Dumper/HtmlDumper.php
+++ b/src/Symfony/Component/VarDumper/Dumper/HtmlDumper.php
@@ -442,30 +442,7 @@ EOHTML;
         }
         $this->lastDepth = $depth;
 
-        // Replaces non-ASCII UTF-8 chars by numeric HTML entities
-        $this->line = preg_replace_callback(
-            '/[\x80-\xFF]+/',
-            function ($m) {
-                $m = unpack('C*', $m[0]);
-                $i = 1;
-                $entities = '';
-
-                while (isset($m[$i])) {
-                    if (0xF0 <= $m[$i]) {
-                        $c = (($m[$i++] - 0xF0) << 18) + (($m[$i++] - 0x80) << 12) + (($m[$i++] - 0x80) << 6) + $m[$i++] - 0x80;
-                    } elseif (0xE0 <= $m[$i]) {
-                        $c = (($m[$i++] - 0xE0) << 12) + (($m[$i++] - 0x80) << 6) + $m[$i++]  - 0x80;
-                    } else {
-                        $c = (($m[$i++] - 0xC0) << 6) + $m[$i++] - 0x80;
-                    }
-
-                    $entities .= '&#'.$c.';';
-                }
-
-                return $entities;
-            },
-            $this->line
-        );
+        $this->line = mb_convert_encoding($this->line, 'HTML-ENTITIES', 'UTF-8');
 
         if (-1 === $depth) {
             AbstractDumper::dumpLine(0);
diff --git a/src/Symfony/Component/VarDumper/Tests/HtmlDumperTest.php b/src/Symfony/Component/VarDumper/Tests/HtmlDumperTest.php
index 14e5eb9d6d..56d286acb1 100644
--- a/src/Symfony/Component/VarDumper/Tests/HtmlDumperTest.php
+++ b/src/Symfony/Component/VarDumper/Tests/HtmlDumperTest.php
@@ -52,7 +52,7 @@ class HtmlDumperTest extends \PHPUnit_Framework_TestCase
             $closure54 = <<<EOTXT
 
     <span class=sf-dump-meta>class</span>: "<span class=sf-dump-str title="48 characters">Symfony\Component\VarDumper\Tests\HtmlDumperTest</span>"
-    <span class=sf-dump-meta>this</span>: <abbr title="Symfony\Component\VarDumper\Tests\HtmlDumperTest" class=sf-dump-note>HtmlDumperTest</abbr> {{$r} &#8230;}
+    <span class=sf-dump-meta>this</span>: <abbr title="Symfony\Component\VarDumper\Tests\HtmlDumperTest" class=sf-dump-note>HtmlDumperTest</abbr> {{$r} &%s;}
 EOTXT;
         }
 
@@ -68,8 +68,8 @@ EOTXT;
   <span class=sf-dump-key>4</span> => <span class=sf-dump-num>INF</span>
   <span class=sf-dump-key>5</span> => <span class=sf-dump-num>-INF</span>
   <span class=sf-dump-key>6</span> => <span class=sf-dump-num>{$intMax}</span>
-  "<span class=sf-dump-key>str</span>" => "<span class=sf-dump-str title="5 characters">d&#233;j&#224;</span>\\n"
-  <span class=sf-dump-key>7</span> => b"<span class=sf-dump-str title="2 binary or non-UTF-8 characters">&#233;</span>\\x00"
+  "<span class=sf-dump-key>str</span>" => "<span class=sf-dump-str title="5 characters">d&%s;j&%s;</span>\\n"
+  <span class=sf-dump-key>7</span> => b"<span class=sf-dump-str title="2 binary or non-UTF-8 characters">&%s;</span>\\x00"
   "<span class=sf-dump-key>[]</span>" => []
   "<span class=sf-dump-key>res</span>" => <span class=sf-dump-note>stream resource</span> <a class=sf-dump-ref>@{$res}</a><samp>
     <span class=sf-dump-meta>wrapper_type</span>: "<span class=sf-dump-str title="9 characters">plainfile</span>"
@@ -109,7 +109,7 @@ EOTXT;
   "<span class=sf-dump-key>snobj</span>" => <a class=sf-dump-ref href=#{$dumpId}-ref03 title="2 occurrences">&amp;3</a> {<a class=sf-dump-ref href=#{$dumpId}-ref2%d title="3 occurrences">#%d</a>}
   "<span class=sf-dump-key>snobj2</span>" => {<a class=sf-dump-ref href=#{$dumpId}-ref2%d title="3 occurrences">#%d</a>}
   "<span class=sf-dump-key>file</span>" => "<span class=sf-dump-str title="%d characters">{$var['file']}</span>"
-  b"<span class=sf-dump-key>bin-key-&#233;</span>" => ""
+  b"<span class=sf-dump-key>bin-key-&%s;</span>" => ""
 </samp>]
 </bar>
 
@@ -120,9 +120,6 @@ EOTXT
         );
     }
 
-    /**
-     * @requires extension mbstring
-     */
     public function testCharset()
     {
         $var = mb_convert_encoding('Словарь', 'CP1251', 'UTF-8');
diff --git a/src/Symfony/Component/VarDumper/composer.json b/src/Symfony/Component/VarDumper/composer.json
index 8bffc384cd..51c667cbf0 100644
--- a/src/Symfony/Component/VarDumper/composer.json
+++ b/src/Symfony/Component/VarDumper/composer.json
@@ -16,7 +16,8 @@
         }
     ],
     "require": {
-        "php": ">=5.3.9"
+        "php": ">=5.3.9",
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
         "twig/twig": "~1.20|~2.0"
diff --git a/src/Symfony/Component/Yaml/Inline.php b/src/Symfony/Component/Yaml/Inline.php
index e3470aa5f5..ca0b603abf 100644
--- a/src/Symfony/Component/Yaml/Inline.php
+++ b/src/Symfony/Component/Yaml/Inline.php
@@ -52,7 +52,7 @@ class Inline
             return '';
         }
 
-        if (function_exists('mb_internal_encoding') && ((int) ini_get('mbstring.func_overload')) & 2) {
+        if (2 /* MB_OVERLOAD_STRING */ & (int) ini_get('mbstring.func_overload')) {
             $mbEncoding = mb_internal_encoding();
             mb_internal_encoding('ASCII');
         }
diff --git a/src/Symfony/Component/Yaml/Parser.php b/src/Symfony/Component/Yaml/Parser.php
index 04f2237be2..a6c0f291c2 100644
--- a/src/Symfony/Component/Yaml/Parser.php
+++ b/src/Symfony/Component/Yaml/Parser.php
@@ -62,7 +62,7 @@ class Parser
         $value = $this->cleanup($value);
         $this->lines = explode("\n", $value);
 
-        if (function_exists('mb_internal_encoding') && ((int) ini_get('mbstring.func_overload')) & 2) {
+        if (2 /* MB_OVERLOAD_STRING */ & (int) ini_get('mbstring.func_overload')) {
             $mbEncoding = mb_internal_encoding();
             mb_internal_encoding('UTF-8');
         }