diff --git a/openupgrade_scripts/apriori.py b/openupgrade_scripts/apriori.py
index cd3d3a9a9ec2..18579ba763fb 100644
--- a/openupgrade_scripts/apriori.py
+++ b/openupgrade_scripts/apriori.py
@@ -143,6 +143,18 @@
     # OCA/...
 }
 
+# Deleted modules
+deleted_modules = [
+    # odoo
+    "base_gengo",
+    "im_support",
+    "l10n_cn_standard",
+    "theme_bootswatch",
+    "web_diagram",
+    "website_gengo",
+    # OCA/...
+]
+
 # only used here for upgrade_analysis
 renamed_models = {
     # odoo
diff --git a/openupgrade_scripts/scripts/om_account_accountant/14.0.8.1.0/pre-migration.py b/openupgrade_scripts/scripts/om_account_accountant/14.0.8.1.0/pre-migration.py
new file mode 100644
index 000000000000..ba3427bba025
--- /dev/null
+++ b/openupgrade_scripts/scripts/om_account_accountant/14.0.8.1.0/pre-migration.py
@@ -0,0 +1,38 @@
+# Copyright 2025 TechnoLibre  <https://technolibre.ca>
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+import logging
+
+from openupgradelib import openupgrade
+
+from odoo.tools.translate import _
+
+_logger = logging.getLogger(__name__)
+
+
+def change_owner_group_fiscal_year(env):
+    """When installing om_account_accountant, got a conflict duplicated group group_fiscal_year"""
+    imd = env["ir.model.data"].sudo()
+    # Remove any stale/duplicate mapping of the old XMLID
+    imd.search(
+        [
+            ("module", "=", "account"),
+            ("name", "=", "group_fiscal_year"),
+            ("model", "=", "res.groups"),
+        ]
+    ).unlink()
+    imd = env["res.groups"].sudo()
+    # Remove any stale/duplicate mapping of the old XMLID
+    imd.search(
+        [
+            (
+                "name",
+                "=",
+                "Allow to define fiscal years of more or less than a year",
+            ),
+        ]
+    ).unlink()
+
+
+@openupgrade.migrate()
+def migrate(env, version):
+    change_owner_group_fiscal_year(env)