diff --git a/admin/environment.xml b/admin/environment.xml
index b3d2fb2c387..dc243a3870b 100644
--- a/admin/environment.xml
+++ b/admin/environment.xml
@@ -227,9 +227,9 @@
     <PHP version="5.2.8" level="required">
     </PHP>
     <PHP_EXTENSIONS>
-      <PHP_EXTENSION name="iconv" level="optional">
+      <PHP_EXTENSION name="iconv" level="required">
         <FEEDBACK>
-          <ON_CHECK message="iconvrecommended" />
+          <ON_CHECK message="iconvrequired" />
         </FEEDBACK>
       </PHP_EXTENSION>
       <PHP_EXTENSION name="mbstring" level="optional">
diff --git a/lang/en_utf8/admin.php b/lang/en_utf8/admin.php
index 231d9a2cab2..184b5d1619c 100644
--- a/lang/en_utf8/admin.php
+++ b/lang/en_utf8/admin.php
@@ -514,6 +514,7 @@ $string['htmlsettings'] = 'HTML settings';
 $string['http'] = 'HTTP';
 $string['httpsecurity'] = 'HTTP security';
 $string['iconvrecommended'] = 'Installing the optional ICONV library is highly recommended in order to improve site performance, particularly if your site is supporting non-Latin languages.';
+$string['iconvrequired'] = 'Installing the optional ICONV library is required.';
 $string['ignore'] = 'Ignore';
 $string['importlangreminder'] = 'The database migration process is commencing. You will need to <b>log in again</b> for the upgrade to take effect. Please install unicode language packs as soon as possible from Admin->Lang->Lang Import Utility <b>after</b> the database migration process is completed.';
 $string['importtimezones'] = 'Update complete list of timezones';