diff --git a/INSTALL.txt b/INSTALL.txt
index a02d19c9da7aa076bf78f7555910b183560ad010..2dd21220a85d1b3528766096f6df9349b17e2d2b 100644
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -18,7 +18,7 @@ Drupal requires a web server, PHP 4 (4.3.5 or greater) or PHP 5
 (http://www.php.net/) and either MySQL (http://www.mysql.com/) or PostgreSQL
 (http://www.postgresql.org/). The Apache web server and MySQL database are
 recommended; other web server and database combinations such as IIS and
-PostgreSQL have been tested to a lesser extent. When using MySQL, version 4.1.1
+PostgreSQL have been tested to a lesser extent. When using MySQL, version 5.0
 or greater is recommended to assure you can safely transfer the database.
 
 For more detailed information about Drupal requirements, see "Requirements"
diff --git a/includes/common.inc b/includes/common.inc
index 789a016737ae2870833d0218cac700b13874c326..3e41439f07cdea1dec92132c48133b77cdd3ad14 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -1567,13 +1567,6 @@ function base_path() {
   return $GLOBALS['base_path'];
 }
 
-/**
- * Provide a substitute clone() function for PHP4.
- */
-function drupal_clone($object) {
-  return version_compare(phpversion(), '5.0') < 0 ? $object : clone($object);
-}
-
 /**
  * Add a <link> tag to the page's HEAD.
  */
diff --git a/modules/contact/contact.pages.inc b/modules/contact/contact.pages.inc
index dc7d631c976bb86b8caa110a69c96cb0a7dd93a5..82d1bb95f40b4d8b197698fbf5fd25435a62f1ab 100644
--- a/modules/contact/contact.pages.inc
+++ b/modules/contact/contact.pages.inc
@@ -106,7 +106,7 @@ function contact_mail_page() {
  */
 function contact_mail_page_validate($form, &$form_state) {
   if (!$form_state['values']['cid']) {
-    form_set_error('category', t('You must select a valid category.'));
+    form_set_error('cid', t('You must select a valid category.'));
   }
   if (!valid_email_address($form_state['values']['mail'])) {
     form_set_error('mail', t('You must enter a valid e-mail address.'));
diff --git a/modules/node/node.module b/modules/node/node.module
index 77c2c875e104f38776d81cc98526bfa4b770f10e..54160f8a33c6bfc46b056f44a6522bbc7485414b 100644
--- a/modules/node/node.module
+++ b/modules/node/node.module
@@ -707,7 +707,7 @@ function node_load($param = array(), $revision = NULL, $reset = NULL) {
     if ($cachable) {
       // Is the node statically cached?
       if (isset($nodes[$param])) {
-        return is_object($nodes[$param]) ? drupal_clone($nodes[$param]) : $nodes[$param];
+        return is_object($nodes[$param]) ? clone $nodes[$param] : $nodes[$param];
       }
     }
     $cond = 'n.nid = %d';
@@ -764,7 +764,7 @@ function node_load($param = array(), $revision = NULL, $reset = NULL) {
       }
     }
     if ($cachable) {
-      $nodes[$node->nid] = is_object($node) ? drupal_clone($node) : $node;
+      $nodes[$node->nid] = is_object($node) ? clone $node : $node;
     }
   }
 
@@ -2724,7 +2724,7 @@ function node_unpublish_by_keyword_action_submit($form, $form_state) {
  */
 function node_unpublish_by_keyword_action($node, $context) {
   foreach ($context['keywords'] as $keyword) {
-    if (strstr(node_view(drupal_clone($node)), $keyword) || strstr($node->title, $keyword)) {
+    if (strstr(node_view(clone $node), $keyword) || strstr($node->title, $keyword)) {
       $node->status = 0;
       watchdog('action', 'Set @type %title to unpublished.', array('@type' => node_get_types('name', $node), '%title' => $node->title));
       break;
diff --git a/modules/node/node.pages.inc b/modules/node/node.pages.inc
index aef2308c721a0115625df02feec55b8b5c02009d..dc3e529cbcc73ad2090c99f4f5b2d733fa2e3ba6 100644
--- a/modules/node/node.pages.inc
+++ b/modules/node/node.pages.inc
@@ -394,7 +394,7 @@ function node_preview($node) {
     // Display a preview of the node.
     // Previewing alters $node so it needs to be cloned.
     if (!form_get_errors()) {
-      $cloned_node = drupal_clone($node);
+      $cloned_node = clone $node;
       $cloned_node->build_mode = NODE_BUILD_PREVIEW;
       $output = theme('node_preview', $cloned_node);
     }
@@ -432,7 +432,7 @@ function theme_node_preview($node) {
   if ($preview_trimmed_version) {
     drupal_set_message(t('The trimmed version of your post shows what your post looks like when promoted to the main page or when exported for syndication.<span class="no-js"> You can insert the delimiter "&lt;!--break--&gt;" (without the quotes) to fine-tune where your post gets split.</span>'));
     $output .= '<h3>'. t('Preview trimmed version') .'</h3>';
-    $output .= node_view(drupal_clone($node), 1, FALSE, 0);
+    $output .= node_view(clone $node, 1, FALSE, 0);
     $output .= '<h3>'. t('Preview full version') .'</h3>';
     $output .= node_view($node, 0, FALSE, 0);
   }
diff --git a/modules/taxonomy/taxonomy.module b/modules/taxonomy/taxonomy.module
index af40899a5b2a3ceace47b8627b28710142d30c3e..d649a7bc6b4a1ce8ea6e8d9a9eb832dd66a6fa4a 100644
--- a/modules/taxonomy/taxonomy.module
+++ b/modules/taxonomy/taxonomy.module
@@ -838,7 +838,7 @@ function taxonomy_get_tree($vid, $parent = 0, $depth = -1, $max_depth = NULL) {
   if (!empty($children[$vid][$parent])) {
     foreach ($children[$vid][$parent] as $child) {
       if ($max_depth > $depth) {
-        $term = drupal_clone($terms[$vid][$child]);
+        $term = clone $terms[$vid][$child];
         $term->depth = $depth;
         // The "parent" attribute is not useful, as it would show one parent only.
         unset($term->parent);