Do we need to change the Financial year preffix to the auto generated invoices, manually or it auto upgrades?

Let's figure out if you need to change the FY prefix invoice numbers every year in QuickBooks Online (QBO), @bala-stasislabs-. This way, you can manage your sales transactions accordingly.

When you use the Custom transaction numbers feature, you can set your own numbering preference (any number or letter format) on your sales forms like 2021-22-***. However, the FY prefix to the auto-generated invoice numbers won't automatically be upgraded by the beginning of every year (April 1st). With this, you'll (admin/standard user) have to manually change it every fiscal year.

Since you've already turned on the Custom transaction numbers feature (based on your description), follow these steps to change the FY prefix invoice numbers:

1. Go to the Sales menu.
2. Select Invoices.
3. Open an invoice or any sales form and select Edit invoice or select Create invoice to create a new invoice.
4. In the Invoice no. field, enter the custom number or letter sequence you want to use for your forms. The sequence you set here applies to all sales forms.
5. Select Save or Save and close.

Once you have set up your custom invoice numbering, turn off the Custom transaction numbers feature. This will help prevent accidental changes to your numbering. You can learn more about this by checking out this article: How to change the invoice number on sales forms.

Also, with GST implementation, your invoices will need to be GST-compliant. If you wish to know what should be included in a GST-ready invoice and how you can customise your form, please refer to this article: Customise invoice for GST.

Let me know if there's anything else you need or concerns about invoices numbers and managing sales transactions in QBO. I'll gladly help. Take care always, @bala-stasislabs-.