diff --git a/partner_communication_switzerland/data/sponsorship_action_rules.xml b/partner_communication_switzerland/data/sponsorship_action_rules.xml
index 1fb8e99fd..9c512e2a1 100644
--- a/partner_communication_switzerland/data/sponsorship_action_rules.xml
+++ b/partner_communication_switzerland/data/sponsorship_action_rules.xml
@@ -46,7 +46,7 @@
             <field name="model_id" ref="model_correspondence"/>
             <field name="kind">on_time</field>
             <field name="trg_date_id" ref="field_correspondence_sent_date"/>
-            <field name="filter_domain">[('communication_id.state', '=', 'done'), ('communication_id.send_mode', '=', 'digital'), ('email_read', '=', None)]</field>
+            <field name="filter_domain">[('communication_id.state', '=', 'done'), ('communication_id.send_mode', '=', 'digital'), ('email_read', '=', None), ('letter_delivered', '=', False)]</field>
             <field name="trg_date_range">3</field>
             <field name="trg_date_range_type">day</field>
             <field name="server_action_ids" eval="[(6, 0, [ref('send_unread_b2s')])]"/>