This can be achieved through setting up invoice series numbering with different validity dates.  You can find the invoice series relevant (i.e. used for the types of invoices) by looking at the Customer Invoice Types window. 

From the Invoice Series you can drill into Invoice Number Series. 

Here you can add different series with starting dates per month. The invoice number gets added to an invoice when it is printed so it will work for any invoices created in one month but printed in another. We can use migration jobs to populate this table.

Yes, there is such option to use Invoice Number Series, however it does not allow us to create Invoice No other than numeric values identyfying year, month and consecutive number for example number in range from 2022110001 to 2022119999 for November 2022. 

What if we already have invoices from other system and need to create new ones in IFS in the same numbering manner - last invoice was 01/11-2022. New one should take 02/11-2022. Is it possible to configure it somehow?

Correct, I’m afraid the IFS numbering series only supports numerical numbering.

Are you talking about invoices generated in IFS or manual customer invoices? The latter is used for invoices created in another system and there the invoice ID can be alphanumeric. If it’s to continue the same series as in the old system for customer order, project or instant invoice types then this is not an option.

The invoice date is something that is on the invoice, so maybe it is worth exploring a custom field to create an additional invoice reference number along with the IFS standard invoice ID by using the invoice date as a driver for the numbering sequence. It is this additional custom field that we can display in the invoice PDF printout and we can add this reference field into the analysis windows too 

Exactly my idea, the last one you mentioned . Thank you for confirmation. So far we used Manual Customer Invoice, but we need to switch into printable mode and Instant Invoice seems a natural choice. I hoped to find out a standard functionality which would provide the continuity and consistency of data. If not, probably the additional custom field will be the solution.

Thank you. 

P.S. BTW are custom fields from custom tabs available to use in printout layouts? 

That’s great.

I can confirm that custom fields are available to be used in the report designer to be included in the printout documents.