diff --git a/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php b/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
index 65894340cb..5998759423 100644
--- a/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
+++ b/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
@@ -49,6 +49,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
         'fr' => 'fra',
         'gn' => 'grn',
         'hy' => 'hye',
+        'hr' => 'hrv',
         'ik' => 'ipk',
         'is' => 'isl',
         'iu' => 'iku',
@@ -76,6 +77,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
         'sc' => 'srd',
         'sk' => 'slk',
         'sq' => 'sqi',
+        'sr' => 'srp',
         'sw' => 'swa',
         'uz' => 'uzb',
         'yi' => 'yid',
@@ -164,10 +166,13 @@ class LanguageDataGenerator extends AbstractDataGenerator
 
     private function generateAlpha2ToAlpha3Mapping(ArrayAccessibleResourceBundle $metadataBundle)
     {
-        $aliases = $metadataBundle['languageAlias'];
+        // Data structure has changed in ICU 5.5 from "languageAlias" to "alias->language"
+        $aliases = $metadataBundle['languageAlias'] ?: $metadataBundle['alias']['language'];
         $alpha2ToAlpha3 = array();
 
         foreach ($aliases as $alias => $language) {
+            // $language is a string before ICU 5.5
+            $language = is_string($language) ? $language : $language['replacement'];
             if (2 === strlen($language) && 3 === strlen($alias)) {
                 if (isset(self::$preferredAlpha2ToAlpha3Mapping[$language])) {
                     // Validate to prevent typos
@@ -181,12 +186,13 @@ class LanguageDataGenerator extends AbstractDataGenerator
                     }
 
                     $alpha3 = self::$preferredAlpha2ToAlpha3Mapping[$language];
+                    $alpha2 = is_string($aliases[$alpha3]) ? $aliases[$alpha3] : $aliases[$alpha3]['replacement'];
 
-                    if ($language !== $aliases[$alpha3]) {
+                    if ($language !== $alpha2) {
                         throw new RuntimeException(
                             'The statically set three-letter mapping '.$alpha3.' '.
                             'for the language code '.$language.' seems to be '.
-                            'an alias for '.$aliases[$alpha3].'. Wrong mapping?'
+                            'an alias for '.$alpha2.'. Wrong mapping?'
                         );
                     }
 
diff --git a/src/Symfony/Component/Intl/Resources/bin/icu.ini b/src/Symfony/Component/Intl/Resources/bin/icu.ini
index 119f2431a4..e6fdd01d4a 100644
--- a/src/Symfony/Component/Intl/Resources/bin/icu.ini
+++ b/src/Symfony/Component/Intl/Resources/bin/icu.ini
@@ -10,4 +10,5 @@
 51 = http://source.icu-project.org/repos/icu/icu/tags/release-51-2/source
 52 = http://source.icu-project.org/repos/icu/icu/tags/release-52-1/source
 53 = http://source.icu-project.org/repos/icu/icu/tags/release-53-1/source
-54 = http://source.icu-project.org/repos/icu/icu/tags/release-54-rc/source
+54 = http://source.icu-project.org/repos/icu/icu/tags/release-54-1/source
+55 = http://source.icu-project.org/repos/icu/icu/tags/release-55-1/source