diff --git a/inc/infoutils.php b/inc/infoutils.php
index ac59d94885b85da1395a2639f815c655eda15317..c2db31f7d7fe78048ac643f9e1b5b0b45136912c 100644
--- a/inc/infoutils.php
+++ b/inc/infoutils.php
@@ -81,10 +81,8 @@ function check(){
 
   msg('DokuWiki version: '.getVersion(),1);
 
-  if(version_compare(phpversion(),'4.3.3','<')){
-    msg('Your PHP version is too old ('.phpversion().' vs. 4.3.3+ recommended)',-1);
-  }elseif(version_compare(phpversion(),'4.3.10','<')){
-    msg('Consider upgrading PHP to 4.3.10 or higher for security reasons (your version: '.phpversion().')',0);
+  if(version_compare(phpversion(),'5.0.0','<')){
+    msg('Your PHP version is too old ('.phpversion().' vs. 5.0.0+ recommended)',-1);
   }else{
     msg('PHP version '.phpversion(),1);
   }
diff --git a/install.php b/install.php
index 3f031ecd12104ffbd879553b8ec286b7e043e0b8..07f69f24bfafbdd46524e5e4ef20192b92d8eb15 100644
--- a/install.php
+++ b/install.php
@@ -424,8 +424,8 @@ function check_functions(){
     global $lang;
     $ok = true;
 
-    if(version_compare(phpversion(),'4.3.3','<')){
-        $error[] = sprintf($lang['i_phpver'],phpversion(),'4.3.3');
+    if(version_compare(phpversion(),'5.0.0','<')){
+        $error[] = sprintf($lang['i_phpver'],phpversion(),'5.0.0');
         $ok = false;
     }
 
@@ -434,7 +434,7 @@ function check_functions(){
                          'glob header ignore_user_abort ini_get mail mkdir '.
                          'ob_start opendir parse_ini_file readfile realpath '.
                          'rename rmdir serialize session_start unlink usleep '.
-                         'preg_replace file_get_contents');
+                         'preg_replace file_get_contents htmlspecialchars_decode');
 
     if (!function_exists('mb_substr')) {
       $funcs[] = 'utf8_encode';