When you enter a registration number for your business or for a customer, Sliptree now checks it against the official format of the company's country. A mistyped number is caught right in the form, before it ends up printed on an invoice.
Registration numbers in 23 countries are now format-checked — Estonian registry codes are 8 digits, Finnish business IDs look like 1234567-8, Swedish organisation numbers like 556677-8899, and so on. Where a country builds a check digit into its numbers, we verify that too, so even a number with the right length but two digits swapped gets flagged. When a number doesn't pass, the form tells you what a number from that country should look like.
There's no need to strip spaces, dots or other separators before pasting a number. A Norwegian VAT number written as NO 974 760 673 MVA, or a Swiss one as CHE-109.322.551 MWST, is understood as-is. VAT number checking also became more accurate: certain valid French, Swiss, Norwegian and UK VAT numbers that were previously rejected are now accepted.
The check runs when a number is entered or changed. Numbers that are already saved stay as they are — editing other details of your business or a customer, or re-importing an unchanged customer list, works exactly as before.