Hello all,

I thank you all for engaging with this feature request.

We have introduced credit and debit notes to our invoicing system. Starting with WHMCS 9.0, non-Draft invoices are immutable. This means you cannot edit transactions on an invoice or add or remove items from it.

This improvement can help with invoice management and tax compliance by ensuring all invoices list transactions consistently.

We have listened, and this is delivered in line with best practices.

For more information, please review:

https://docs.whmcs.com/releases/9-0/9-0-release-notes/#credit-and-debit-notes