All your links state the opposite of your statement. They all say that the invoice numbering must be consecutive. And for me it is clear that consecutive means consecutive in time otherwise it means nothing. And time is recorded by the accounting date.
Even if this were true (which I do not understand from your links), it does not prevent to use Tryton at all.
The links state that basing on German law an invoice sequence must provide unique numbers. And being consecutive is the primary property of a sequence otherwise is is a random series. That doesn’t mean at all that a sequence must be coupled to a date or something else.
I think there is enough evidence that it is true. Of course the current constraint does not prevent to use Tryton at all. We are talking about “Prevent using same sequence on earlier customer invoice” which is allowed in Germany.
Indeed in Spanish documentation “time” for customer invoices is issued time; and it is recorded by invoice date.
It means that otherwise if you can not order invoices, you can not have consecutive property.
And which is allowed in Tryton but enforcing consecutive property.
Well it is a little bit more complex because it is a combination of invoice and accounting date and the period of the sequence.
While I agree with @yangoon that there is no combined constraint on date and numbers of the invoice number I consider the issuing of invoices with a date in the past as bad practice. Especially since the date of delivery/service needs to be part of the invoice. Even if the business transaction to which an invoice relates is in the past the invoice date should be not older than today. I think the proposed changes will allow Tryton to be used in Germany for issuing invoices without any problems.
For the record, this is the only place where the requirements for an invoice number in germany are written down in german law (Section 14.5 Paragraph 10):
There are no requirements other than those described there.
In The Netherlands the same applies as for Germany. Just a sequence of consecutive numbers. It is possible to have multiple sequences but there should be a good reason for that.
I totally agree that invoice date in customer invoices should be preferably today and date in past should be avoided. This is not applicable to accounting date which should be the date when the goods are delivered or services are provided.
So for this reason I don’t see why invoice number must use accounting date to create consecutive numbering in time. Because imho it is not achieved in the moment I post invoices with accounting date in the past.
Finally we have official answer about what date to use in customer invoice numbering (note that first two pages were removed because they contained sensitive information).
As I said along thread, in Spain the date to use for getting a consecutive numbering in customer invoices is “invoice date”.
una recomendacion borra el csv del documento porque se puede acceder a los datos privados.
un saludo