Following Brexit on January 1st 2021, companies in Northern Ireland have a new VAT number starting with XI instead of GB. More info: https://www.gov.uk/government/publications/accounting-for-vat-on-goods-moving-between-great-britain-and-northern-ireland-from-1-january-2021/check-when-you-are-trading-under-the-northern-ireland-protocol-if-you-are-vat-registered-business stdnum support the new XI VAT from 1.16 https://github.com/arthurdejong/python-stdnum/commit/b93d69581f35aa18e7fdd52b3f7fdf06770215e3 This patch add temporary support in base_vat until the new version is available on the Debian package repository Community tracked issue https://github.com/odoo/odoo/issues/64891 opw-2461322 closes odoo/odoo#67473 X-original-commit: 7e7d8731aa5679123100311b573a65ae23f3db99 Signed-off-by: William André (wan) <wan@odoo.com> Signed-off-by: agr-odoo <agr-odoo@users.noreply.github.com>