diff --git a/mellon/adapters.py b/mellon/adapters.py
index 0f5b98e..44e9193 100644
--- a/mellon/adapters.py
+++ b/mellon/adapters.py
@@ -331,9 +331,20 @@ class DefaultAdapter:
             name_id = saml_attributes['name_id_content']
         entity_id = saml_attributes['issuer']
         try:
+            to_update = {
+                'nid_format': saml_attributes['name_id_format'],
+                'nid_name_qualifier': saml_attributes.get('name_id_name_qualifier'),
+                'nid_sp_name_qualifier': saml_attributes.get('name_id_sp_name_qualifier'),
+                'nid_sp_provided_id': saml_attributes.get('name_id_sp_provided_id'),
+            }
             saml_identifier = models.UserSAMLIdentifier.objects.select_related('user').get(
                 name_id=name_id, issuer=models_utils.get_issuer(entity_id)
             )
+            # nid_* attributes are new, we must update them if they are not initialized, eventually
+            for key in to_update:
+                if getattr(saml_identifier, key) != to_update[key]:
+                    models.UserSAMLIdentifier.objects.filter(pk=saml_identifier.pk).update(**to_update)
+                    break
             user = saml_identifier.user
             user.saml_identifier = saml_identifier
             logger.info('mellon: looked up user %s with name_id %s from issuer %s', user, name_id, entity_id)
@@ -463,17 +474,25 @@ class DefaultAdapter:
         name_id_content = saml_attributes['name_id_content']
         if saml_attributes['name_id_format'] == lasso.SAML2_NAME_IDENTIFIER_FORMAT_TRANSIENT:
             name_id_content = saml_attributes['transient_name_id_content']
+        to_update = {
+            'nid_format': saml_attributes['name_id_format'],
+            'nid_name_qualifier': saml_attributes.get('name_id_name_qualifier'),
+            'nid_sp_name_qualifier': saml_attributes.get('name_id_sp_name_qualifier'),
+            'nid_sp_provided_id': saml_attributes.get('name_id_sp_provided_id'),
+        }
         saml_id, created = models.UserSAMLIdentifier.objects.get_or_create(
             name_id=name_id_content,
             issuer=models_utils.get_issuer(saml_attributes['issuer']),
             defaults={
                 'user': user,
-                'nid_format': saml_attributes['name_id_format'],
-                'nid_name_qualifier': saml_attributes.get('name_id_name_qualifier'),
-                'nid_sp_name_qualifier': saml_attributes.get('name_id_sp_name_qualifier'),
-                'nid_sp_provided_id': saml_attributes.get('name_id_sp_provided_id'),
+                **to_update,
             },
         )
+        # nid_* attributes are new, we must update them eventually
+        for key in to_update:
+            if getattr(saml_id, key) != to_update[key]:
+                models.UserSAMLIdentifier.objects.filter(pk=saml_id.pk).update(**to_update)
+                break
         if created:
             user.saml_identifier = saml_id
             return user
diff --git a/tests/test_sso_slo.py b/tests/test_sso_slo.py
index 3fedc93..b2b87b4 100644
--- a/tests/test_sso_slo.py
+++ b/tests/test_sso_slo.py
@@ -894,3 +894,31 @@ def test_sso_slo_token(db, app, rf, idp, caplog, django_user_model, freezer):
     assert len(caplog.records) == 0, 'logout failed'
     assert response.location == '/somepath/'
     assert models.SessionIndex.objects.count() == 0
+
+
+def test_sso_slo_update_of_new_fields(db, app, idp, caplog, sp_settings):
+    response = app.get('/login/')
+    url, body, relay_state = idp.process_authn_request_redirect(response['Location'])
+    response = app.post(
+        reverse('mellon_login'), params={'SAMLResponse': body, 'RelayState': relay_state}
+    ).follow()
+    # violent logout
+    app.session.flush()
+
+    # remove existing fields
+    models.UserSAMLIdentifier.objects.all().update(
+        nid_format=None, nid_name_qualifier=None, nid_sp_name_qualifier=None, nid_sp_provided_id=None
+    )
+
+    response = app.get('/login/')
+    url, body, relay_state = idp.process_authn_request_redirect(response['Location'])
+    response = app.post(
+        reverse('mellon_login'), params={'SAMLResponse': body, 'RelayState': relay_state}
+    ).follow()
+
+    # check logout works
+    response = app.get('/logout/')
+    url = idp.process_logout_request_redirect(response.location)
+    caplog.clear()
+    response = app.get(url)
+    assert len(caplog.records) == 0, 'logout failed'