diff --git includes/update.inc includes/update.inc
index 30cfffd..be45bb7 100644
--- includes/update.inc
+++ includes/update.inc
@@ -735,6 +735,16 @@ function update_fix_d7_requirements() {
     // Rename action description to label.
     db_change_field('actions', 'description', 'label', array('type' => 'varchar', 'length' => 255, 'not null' => TRUE, 'default' => '0'));
 
+    // Add the substr_index() function to PostgreSQL.
+    // Note: this should go into the driver itself, but we have no support
+    // for driver-specific updates yet.
+    if (db_driver() == 'pgsql') {
+      db_query('CREATE OR REPLACE FUNCTION "substring_index"(text, text, integer) RETURNS text AS
+        \'SELECT array_to_string((string_to_array($1, $2)) [1:$3], $2);\'
+        LANGUAGE \'sql\''
+      );
+    }
+
     variable_set('update_d7_requirements', TRUE);
   }
 
diff --git modules/system/system.install modules/system/system.install
index f31abcb..c079602 100644
--- modules/system/system.install
+++ modules/system/system.install
@@ -2115,21 +2115,6 @@ function system_update_7021() {
 }
 
 /**
- * Add the substr_index() function to PostgreSQL.
- *
- * Note: this should go into the driver itself, but we have no support
- * for driver-specific updates yet.
- */
-function system_update_7024() {
-  if (db_driver() == 'pgsql') {
-    db_query('CREATE OR REPLACE FUNCTION "substring_index"(text, text, integer) RETURNS text AS
-      \'SELECT array_to_string((string_to_array($1, $2)) [1:$3], $2);\'
-      LANGUAGE \'sql\''
-    );
-  }
-}
-
-/**
  * Enable field type modules.
  */
 function system_update_7027() {