As in all ERP systems, Shopware assigns unique numbers to all customers, orders, invoices and other documents.
When setting up your shop, you are able to specify a number range which corresponds to an existing number range of an older shop.
Once in live mode, these respective number ranges must not be changed, as current law requires ongoing account numbers. Aside from that, this could also problems when attempting to coordinate with ERP or CRM systems.
For all number ranges, digits 0 through 9 may be used.
Except for number ranges, item numbers may have a prefix attached to them as well.