As described here: https://www.estv.admin.ch/estv/fr/home/mehrwertsteuer/fachinformationen/steuerpflicht/unternehmens-identifikationsnummer--uid-.html The "new" (since 2014) vat number has to be displayed as: CHE 9 numeric digits plus TVA/MWST/IVA e.g.: CHE-123.456.788 TVA This commit removes the previous 6 digits vat number check and regex, and provide accurate examples on the error message displayed if the vatnumber given is wrong. opw-2291581 closes odoo/odoo#59793 X-original-commit: 624e086f0c8ac854fd292d3c6dd14a71ed67b9fe Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>