diff --git a/addons/cetmix_tower_server/migrations/16.0.3.0.0/pre-migration.py b/addons/cetmix_tower_server/migrations/16.0.3.0.0/pre-migration.py
new file mode 100644
index 0000000..8c387d3
--- /dev/null
+++ b/addons/cetmix_tower_server/migrations/16.0.3.0.0/pre-migration.py
@@ -0,0 +1,17 @@
+# Remove the "unique_variable_value_server" constraint for cx_tower_variable_value model
+import logging
+
+_logger = logging.getLogger(__name__)
+
+
+def migrate(cr, version):
+    """Remove the unique_variable_value_server constraint before migration."""
+    cr.execute(
+        """
+        ALTER TABLE cx_tower_variable_value
+        DROP CONSTRAINT IF EXISTS unique_variable_value_server
+        """
+    )
+    _logger.info(
+        "Removed unique_variable_value_server constraint from cx_tower_variable_value"
+    )