I noticed that there’s no locked function (on invoice number prefix) for already created invoices.
For example, I created the prefix - “201401-” and with running number starting with “1”, so it has become “201401-1” which also means Year 2014, Jan, Invoice Number 1.
The issue is, when come end of the month of Feb, I need to change the prefix to “201402-” and the previous invoices created for Jan 2014 has changed from 201401 to 201402.
So there will be a clashed of invoice number. May I know how can I solve this issue?