diff --git a/lib/db/install.xml b/lib/db/install.xml
index 87a8826c2fd..3ea22b7e4e8 100644
--- a/lib/db/install.xml
+++ b/lib/db/install.xml
@@ -909,6 +909,7 @@
       </KEYS>
       <INDEXES>
         <INDEX NAME="userid-name" UNIQUE="true" FIELDS="userid, name"/>
+        <INDEX NAME="name" UNIQUE="false" FIELDS="name"/>
       </INDEXES>
     </TABLE>
     <TABLE NAME="user_lastaccess" COMMENT="To keep track of course page access times, used in online participants block, and participants list">
diff --git a/lib/db/upgrade.php b/lib/db/upgrade.php
index dcd3c5a8cfa..d071e7e71a2 100644
--- a/lib/db/upgrade.php
+++ b/lib/db/upgrade.php
@@ -3059,5 +3059,20 @@ function xmldb_main_upgrade($oldversion) {
         upgrade_main_savepoint(true, 2020110903.05);
     }
 
+    if ($oldversion < 2020110904.05) {
+
+        // Define index name (not unique) to be added to user_preferences.
+        $table = new xmldb_table('user_preferences');
+        $index = new xmldb_index('name', XMLDB_INDEX_NOTUNIQUE, ['name']);
+
+        // Conditionally launch add index name.
+        if (!$dbman->index_exists($table, $index)) {
+            $dbman->add_index($table, $index);
+        }
+
+        // Main savepoint reached.
+        upgrade_main_savepoint(true, 2020110904.05);
+    }
+
     return true;
 }
diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index ebd4aeaec3e..f0815bdbb81 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -6,6 +6,7 @@ information provided here is intended especially for developers.
   has been extended. The new parameter allows the to get the name without escaped characters.
 * The signature of the question_category_options() has been extended. The new parameter allows the to get the categories name
   in the returned array without escaped characters.
+* A new index has been added on mdl_user_preferences.name. This upgrade step might take some time on big sites.
 
 === 3.10.3 ===
 * The behat transformation 'string time to timestamp' no longer supports datetime format. If provided, the format must
diff --git a/version.php b/version.php
index 50cb993c05d..65c96c75048 100644
--- a/version.php
+++ b/version.php
@@ -29,7 +29,7 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$version  = 2020110904.04;              // 20201109      = branching date YYYYMMDD - do not modify!
+$version  = 2020110904.05;              // 20201109      = branching date YYYYMMDD - do not modify!
                                         //         RR    = release increments - 00 in DEV branches.
                                         //           .XX = incremental changes.
 $release  = '3.10.4+ (Build: 20210527)';// Human-friendly version name