diff --git a/tine20/Sales/Model/Address.php b/tine20/Sales/Model/Address.php
index 76e49bd4ce..545880b937 100644
--- a/tine20/Sales/Model/Address.php
+++ b/tine20/Sales/Model/Address.php
@@ -189,11 +189,11 @@ class Sales_Model_Address extends Tinebase_Record_NewAbstract
                 self::QUERY_FILTER => TRUE,
                 self::NULLABLE => TRUE,
             ],
+            // we should drop this column, be aware of upgrade path though!
+            // if you remove it here, Setup/Update/17.php ::update001 will remove it! though it is accessed by later update functions!!!
             self::FLD_CUSTOM1 => [
-                self::LABEL => 'Number Debit', //_('Number Debit')
                 self::TYPE => self::TYPE_STRING,
                 self::NULLABLE => TRUE,
-                self::QUERY_FILTER => TRUE
             ],
             self::FLD_TYPE => [
                 self::TYPE => self::TYPE_STRING,
diff --git a/tine20/Sales/Model/Customer.php b/tine20/Sales/Model/Customer.php
index 992bada728..7acf70e46d 100644
--- a/tine20/Sales/Model/Customer.php
+++ b/tine20/Sales/Model/Customer.php
@@ -6,7 +6,7 @@
  * @subpackage  Model
  * @license     http://www.gnu.org/licenses/agpl.html AGPL Version 3
  * @author      Alexander Stintzing <a.stintzing@metaways.de>
- * @copyright   Copyright (c) 2013-2023 Metaways Infosystems GmbH (http://www.metaways.de)
+ * @copyright   Copyright (c) 2013-2024 Metaways Infosystems GmbH (http://www.metaways.de)
  */
 
 /**
diff --git a/tine20/Sales/Setup/Update/17.php b/tine20/Sales/Setup/Update/17.php
index f9adae4382..e942ccc955 100644
--- a/tine20/Sales/Setup/Update/17.php
+++ b/tine20/Sales/Setup/Update/17.php
@@ -27,6 +27,7 @@ class Sales_Setup_Update_17 extends Setup_Update_Abstract
     const RELEASE017_UPDATE008 = __CLASS__ . '::update008';
     const RELEASE017_UPDATE009 = __CLASS__ . '::update009';
     const RELEASE017_UPDATE010 = __CLASS__ . '::update010';
+    const RELEASE017_UPDATE011 = __CLASS__ . '::update011';
 
     static protected $_allUpdates = [
         self::PRIO_TINEBASE_BEFORE_STRUCT   => [
@@ -58,6 +59,10 @@ class Sales_Setup_Update_17 extends Setup_Update_Abstract
                 self::CLASS_CONST                   => self::class,
                 self::FUNCTION_CONST                => 'update005',
             ],
+            self::RELEASE017_UPDATE011          => [
+                self::CLASS_CONST                   => self::class,
+                self::FUNCTION_CONST                => 'update011',
+            ],
         ],
         self::PRIO_NORMAL_APP_STRUCTURE     => [
             self::RELEASE017_UPDATE009          => [
@@ -401,4 +406,25 @@ public function update010()
         
         $this->addApplicationUpdate(Sales_Config::APP_NAME, '17.10', self::RELEASE017_UPDATE010);
     }
+
+    public function update011()
+    {
+        $this->_db->query('UPDATE ' . SQL_TABLE_PREFIX . Sales_Model_Debitor::TABLE_NAME . ' as a JOIN '
+            . SQL_TABLE_PREFIX . Sales_Model_Customer::TABLE_NAME .' AS b ON a.' . Sales_Model_Debitor::FLD_CUSTOMER_ID . ' = b.id SET a.number = b.number');
+
+        $this->_db->query('UPDATE ' . SQL_TABLE_PREFIX . Sales_Model_Debitor::TABLE_NAME . ' as d JOIN '
+            . SQL_TABLE_PREFIX . Sales_Model_Address::TABLE_NAME . ' AS a ON a.' . Sales_Model_Address::FLD_DEBITOR_ID
+            . ' = d.id SET d.number = a.' . Sales_Model_Address::FLD_CUSTOM1 . ' WHERE a.' . Sales_Model_Address::FLD_CUSTOM1 . ' IS NOT NULL AND a.' . Sales_Model_Address::FLD_CUSTOM1 . ' <> ""');
+
+        $this->_db->query('UPDATE ' . SQL_TABLE_PREFIX . Sales_Model_Debitor::TABLE_NAME . ' as d JOIN '
+            . SQL_TABLE_PREFIX . Sales_Model_Customer::TABLE_NAME .' AS c ON d.' . Sales_Model_Debitor::FLD_CUSTOMER_ID
+            . ' = c.id JOIN ' . SQL_TABLE_PREFIX . Sales_Model_Address::TABLE_NAME . ' AS a ON a.' . Sales_Model_Address::FLD_CUSTOMER_ID
+            . ' = c.id SET d.number = a.' . Sales_Model_Address::FLD_CUSTOM1 . ' WHERE a.' . Sales_Model_Address::FLD_CUSTOM1 . ' IS NOT NULL AND a.' . Sales_Model_Address::FLD_CUSTOM1 . ' <> ""');
+
+        $bucket = Sales_Model_Debitor::class . '#' . Sales_Model_Debitor::FLD_NUMBER . '#' . Sales_Config::getInstance()->{Sales_Config::DEFAULT_DIVISION};
+        $this->getDb()->query('DELETE FROM ' . SQL_TABLE_PREFIX . 'numberable WHERE bucket = "'. $bucket . '"');
+        $this->getDb()->query('INSERT INTO ' . SQL_TABLE_PREFIX . 'numberable (bucket, number) SELECT "' . $bucket . '", ' . Sales_Model_Debitor::FLD_NUMBER . ' FROM ' . SQL_TABLE_PREFIX . Sales_Model_Debitor::TABLE_NAME);
+
+        $this->addApplicationUpdate(Sales_Config::APP_NAME, '17.11', self::RELEASE017_UPDATE011);
+    }
 }