Hello,

We're pleased to announce that a new Invoice Immutability and Credit Note Control is implemented in WHMCS v9.1.

The default state retains full invoice immutability and credit/debit note functionality to ensure financial compliance out of the box, whilst users who do not require such stringent traceability and audit requirements, can now relax it while keeping billing notes, or turn it off entirely.

This will allow you to work with an invoice to suit your requirements.

For more information check out our release highlights: https://docs.whmcs.com/releases/9-1/9-1-release-highlights/
Try it out yourselves, and share your feedback in the v9.1 Beta Discussion Board: https://whmcs.community/forum/664-whmcs-91-beta-discussion/