diff --git a/htdocs/install/mysql/migration/24.0.0-25.0.0.sql b/htdocs/install/mysql/migration/24.0.0-25.0.0.sql
index 364e8c177e4..bb9ab59b4ed 100644
--- a/htdocs/install/mysql/migration/24.0.0-25.0.0.sql
+++ b/htdocs/install/mysql/migration/24.0.0-25.0.0.sql
@@ -78,4 +78,9 @@ UPDATE llx_commande_fournisseurdet SET subprice_ttc = 0 WHERE subprice_ttc <> 0
 UPDATE llx_facture_fourn_det SET pu_ttc = 0 WHERE pu_ttc <> 0 AND EXISTS (SELECT c.rowid FROM llx_const as c WHERE c.name = 'MAIN_VERSION_LAST_UPGRADE' AND c.value < '25.0.0');
 UPDATE llx_supplier_proposaldet SET subprice_ttc = 0 WHERE subprice_ttc <> 0 AND EXISTS (SELECT c.rowid FROM llx_const as c WHERE c.name = 'MAIN_VERSION_LAST_UPGRADE' AND c.value < '25.0.0');
 
+-- Explicit contact address mode flag. NULL keeps the legacy resolution for existing records,
+-- so an existing alternative contact address stays independent from its thirdparty address.
+-- VMYSQL4.1 ALTER TABLE llx_socpeople ADD COLUMN use_thirdparty_address smallint DEFAULT NULL AFTER fk_soc;
+-- VPGSQL8.2 ALTER TABLE llx_socpeople ADD COLUMN use_thirdparty_address smallint DEFAULT NULL;
+
 -- end of migration
diff --git a/htdocs/install/mysql/tables/llx_socpeople.sql b/htdocs/install/mysql/tables/llx_socpeople.sql
index ce980d864c4..14e7423cf80 100644
--- a/htdocs/install/mysql/tables/llx_socpeople.sql
+++ b/htdocs/install/mysql/tables/llx_socpeople.sql
@@ -25,6 +25,7 @@ create table llx_socpeople
   datec				datetime,
   tms				timestamp DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
   fk_soc			integer,									-- lien vers la societe
+  use_thirdparty_address	smallint DEFAULT NULL,					-- 1=use linked thirdparty address, 0=use contact address, null=legacy resolution
   entity			integer DEFAULT 1 NOT NULL,					-- multi company id
   ref_ext           varchar(255),                               -- reference into an external system (not used by dolibarr)
   name_alias        varchar(255),