diff --git a/l10n_it_fatturapa/models/ir_attachment.py b/l10n_it_fatturapa/models/ir_attachment.py
index 816d068a4e62..7fb8611be9a8 100644
--- a/l10n_it_fatturapa/models/ir_attachment.py
+++ b/l10n_it_fatturapa/models/ir_attachment.py
@@ -39,6 +39,7 @@ class FatturaPAAttachment(models.AbstractModel):
     }
     _inherit = [
         "mail.thread",
+        "mail.activity.mixin",
     ]
     _order = "id desc"