I'm here to share a few information about creating estimates, PBMB.

Beta testing is one of the best practice that allows you to test your product with real users before it reaches the market. Usually, this create products that will have an excellent user experience. And yes, you're right that anytime soon this may now be gone. But for now, since creating estimates and converting  with the old or new version is still available, you still have the option on whether you choose the invoice with old or newer version.  For more information on how this happens, I've provided this article for your guide: Create and Send Estimates In QuickBooks Online.

Furthermore, when your customer makes a payment on the invoice, QuickBooks processes the payment and categorizes it into the correct account. To give your more information on how this works, read this article for more details: Record Invoice Payments In QuickBooks Online.

Fill me in if you have any concerns about estimates and invoices. I'll always be right here to help.