diff --git a/documentation/database/patches/patch-0002-add-mailbox-lastsizebytes.sql b/documentation/database/patches/patch-0002-add-mailbox-lastsizebytes.sql
new file mode 100644
index 0000000..70d902d
--- /dev/null
+++ b/documentation/database/patches/patch-0002-add-mailbox-lastsizebytes.sql
@@ -0,0 +1 @@
+ALTER TABLE `{$prefix}mailbox` ADD COLUMN `mailbox_lastsizebytes` INT(10) UNSIGNED AFTER `mailbox_description`;
diff --git a/documentation/database/patches/patch-0002-rename-denormalized-mailbox-lastsizebytes.sql b/documentation/database/patches/patch-0002-rename-denormalized-mailbox-lastsizebytes.sql
deleted file mode 100644
index c4f2902..0000000
--- a/documentation/database/patches/patch-0002-rename-denormalized-mailbox-lastsizebytes.sql
+++ /dev/null
@@ -1,2 +0,0 @@
-ALTER TABLE `{$prefix}mailbox` CHANGE `mailbox_lastquotabytes` `mailbox_lastsizebytes` INT(10) UNSIGNED;
-
diff --git a/scripts/database-upgrade.php b/scripts/database-upgrade.php
index cfca7c8..bfdfc12 100755
--- a/scripts/database-upgrade.php
+++ b/scripts/database-upgrade.php
@@ -1,153 +1,147 @@
 #!/usr/bin/php
 <?php
 # Lavazza Sport Management System by ER Informatica
 # Copyright (C) 2020 Valerio Bozzolan
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 /**
  * This is the script to upgrade the database
  *
  * It will execute the available database patches until the database
  * is to its latest version.
  *
  * To be honest, it also create the database schema if missing.
  */
 
 require __DIR__ . '/../load.php';
 
 echo <<<EOF
  _________________________________________
 / Welcome in the database upgrade script! \
 \ Good luck!                              /
  -----------------------------------------
    \        \
     \        \
      \       _\^
       \    _- oo\
            \---- \______
                  \       )\
                 ||-----||  \
                 ||     ||
 
 EOF;
 
 // path to the documentation directory
 $documentation_path = ABSPATH . '/documentation/database';
 
 // directory to the database patches
 $patch_directory = "$documentation_path/patches";
 
 // execute a random query just to check if we have a database connection
 query( 'SELECT 1' );
 
 // try to check if the database exists
 $database_exists = true;
 try {
 	( new UserAPI() )
 		->limit( 1 )
 		->queryRow();
 
 } catch( Exception $e ) {
 	$database_exists = false;
 }
 
 if( !$database_exists ) {
 	// database schema installation
 	echo "important tables are missing! assuming no database.\n";
 	echo "importing the schema for the first time\n";
 	execute_queries_from_file( "$documentation_path/database-schema.sql" );
-
-	// if we have not imported any database version, just set the latest one
-	$version_exists = get_option( 'database_version', 0 );
-	if( !$version_exists ) {
-		set_option( 'database_version', DATABASE_VERSION );
-	}
 }
 
 // get the current database version
 $current_database_version = get_option( 'database_version', 0 );
 
 // notify about the current status
 printf( "current database version: %d\n", $current_database_version );
 printf( "last database version:    %d\n", DATABASE_VERSION          );
 
 // update to next database versions once at time
 while( $current_database_version < DATABASE_VERSION ) {
 
 	$current_database_version++;
 
 	// note that the patch name can have a name such as 0001-foo.sql
 	$patch_name = sprintf(
 		'patch-%04d-*.sql',
 		$current_database_version
 	);
 
 	// path to the expected patch
 	$patch_path = "$patch_directory/$patch_name";
 
 	// check if there is a database patch to be applied
 	echo "looking for patch $patch_path\n";
 	$found = false;
 	foreach( glob( $patch_path ) as $filename ) {
 		execute_queries_from_file( $filename );
 		$found = true;
 	}
 
 	// actually the unexistence of a patch is good
 	if( !$found ) {
 		echo "\t skipped unexisting patch\n";
 	}
 
 	// update the database version
 	echo "\t increment database version to $current_database_version\n";
 	set_option( 'database_version', $current_database_version );
 }
 
 echo "database upgrade end. good for you!\n";
 
 
 
 
 
 
 /**
  * Execute some queries from a file
  *
  * @param string $file
  */
 function execute_queries_from_file( $file ) {
 	echo "\t executing queries from $file\n";
 
 	// get the patch content
 	$queries = @file_get_contents( $file );
 	if( !$queries ) {
 		throw new Exception( "missing file $file" );
 	}
 
 	// replace the database prefix with the current one
 	//$database_prefix = DB::instance()->getPrefix(); // this cannot work in this phase
 	$database_prefix = $GLOBALS['prefix'];
 	$queries = str_replace( '{$prefix}', $database_prefix,  $queries );
 
 	// execute the patch queries (it will die in case of error)
 	try {
 		multiquery( $queries );
 	} catch( Exception $e ) {
 		echo "\n";
 		printf( "ERROR:\n%s\n\n", $e->getMessage() );
 		printf( "DEBUG QUERIES:\n%s\n", $queries );
 		exit( 1 );
 	}
 }