After upgrading from Self-Employed to Online Simple Start, my invoices created through Self-Employed no longer appear in Online Simple Start. How can I retrieve them????

Welcome back to the Community, @rva_rv_rentals.

You can import your data after upgrading or switching from QuickBooks Self-Employed (QBSE) to QuickBooks Simple-Start (QBSS). However, the option to include the invoices is currently unavailable. You'll need to enter them manually as a workaround.

Here's how:

1. In QBSS, go to the + New button at the top left to get to the Invoices. 
2. Enter the necessary information.
3. Once done, hit Save and close.

For more information, refer to this article: Create invoices in QuickBooks Online.

Just in case, I'll add this article for future reference: Switch from QuickBooks Self-Employed to QuickBooks Online.

Please let me know if you have any other issues or concerns by leaving a comment below. I'm always here to help. Have a great weekend!