GST Invoice Numbering Issue

We have a situation with the invoice numbering.

  1. Our invoice numbering has been disrupted due to adding Opening invoices as ERPnext
    generated Invoice numbers in current Invoice series therefore disrupting the invoice numbering [Opening invoices should have been added before starting transactions though]
  2. Some invoice numbers are more than 16 digit (eg.ACC-SINV-2020-00001) , which is not allowed as per GST rules
  3. To rectify No#2, we changed the invoice numbering (to ACC-2020-00002), we reset the series to start from where it last stopped
  4. We have generated some eway bills with these invoice numbers

We realised that we might face the following problems

  1. Invoice cannot be more than 16 digits, which is the case with some of our invoice numbers
  2. Series is disrupted/not in sequential order because of opening invoices eg ACC-SINV-2020-00001 to ACC-SINV-2020-00010 then the number continues from ACC-SINV-2020-00015 to ACC-SINV-2020-00020 (11 to 14 are opening invoices)

We thought of the following solution, would like to know if this would solve the problem:
We can regenerate invoice number serially based on date [in a custom field] and send revised Invoices to customers. However, What do we do for invoices where Eway bill has been generated with old invoice number Kindly guide us what can be done in this matter.

Thanks for reading through such a long post!