WHMCS 9.0.1 – Unpaid Invoice Editing Restriction & Cancel Permission Requiring Delete Permission

[Ebin V Thomas]

Hello Everyone,

We are currently using WHMCS version 9.0.1 and after upgrading, we have noticed two issues related to invoice management and staff permissions. We would appreciate clarification from the community.

1. Unpaid Invoice Cannot Be Edited

When trying to modify an unpaid invoice, the system shows:

"This is an Unpaid Invoice. You cannot modify an Invoice that is Unpaid."

Previously, we were able to edit unpaid invoices in cases of pricing corrections, tax adjustments, or client-requested changes. We are unable to find any setting that allows editing unpaid invoices in version 9.0.1.

Is this now the intended behavior?
Is there any supported method to allow editing unpaid invoices without marking them as paid first?

 

2. Cancel Invoice Permission Requires Delete Permission

We assign the "Cancel Invoice" permission to specific employees so they can cancel invoices when there are billing errors or mismatches. The cancel action keeps proper logs and maintains an audit trail, which is important for internal control.

However, it appears that the Cancel Invoice permission now requires the Delete Invoice permission to function. This forces us to grant both Cancel and Delete permissions.

This creates a concern because if Delete permission is given, staff may delete invoices instead of cancelling them. Deleted invoices do not provide the same level of audit visibility, and it becomes difficult to track what was removed and why.

Our requirement is to allow invoice cancellation with proper logging, but not allow invoice deletion.

Has anyone else faced this in 9.0.1?
Is this expected behavior, or is there a way to separate Cancel and Delete permissions properly?

Looking forward to feedback from the community.

Thanks in advance.

[Easy Green Hosting]

It's an intended behaviour, explained here: https://docs.whmcs.com/9-0/billing-and-invoicing/invoice-management/

[Ebin V Thomas]

Thank you for the clarification and the documentation link.

I understand that this is now intended behaviour and that the recommended workflow is to create a Draft Invoice, make changes, and then publish it.

However, we have a few practical workflow concerns and would appreciate guidance.

1. Linking New Invoice to Existing Service

If we cancel an unpaid invoice and manually create a new one, the newly created invoice is not automatically linked to the original service. It becomes a separate invoice not associated with that service’s billing cycle.

For example:

• A service invoice is generated with a late fee.

• The customer requests removal of the late fee.

• Now we must cancel the original invoice.

• If we create a new invoice manually without the late fee, it does not remain properly connected to the service renewal.

Is there a supported way to create a replacement invoice that remains linked to the existing service and billing cycle?

If the new Draft Invoice workflow allows proper tagging or association with the existing service, that would solve our concern.

2. Editing Invoice Line Items for Adjustments

Earlier, we could edit the invoice line item description and adjust the amount. For example:

• Mention “Special pricing adjustment for this month”

• Reduce invoice amount by half

• Keep everything within the same invoice record

Now that unpaid invoices cannot be edited, this flexibility is gone. The only option appears to be cancellation and re-creation, which breaks continuity and increases administrative overhead.

Is there a recommended best practice for handling such partial adjustments while keeping service linkage intact?

3. Partial Usage / Refund Scenarios

Another scenario:

• A customer pays via direct transfer.

• We add funds manually and deploy the service.

• After 20 days, the customer requests a refund for the remaining 10 days.

• We process a partial refund externally.

If we want to:

• Calculate usage

• Deduct our effort or processing charges

• Clearly document the breakdown in an invoice format

How should this be handled under the new workflow?
Is it possible to generate an adjustment invoice or credit note that clearly reflects these calculations and keeps accounting clean?

We fully understand the intent behind protecting invoice integrity, especially for compliance and audit reasons. Our main concern is maintaining service linkage, transparency, and clean billing history while still handling real-world adjustments.

Appreciate any clarification on best practices under 9.0.1.

Thank you.

[Easy Green Hosting]

good points! I don't know, hopefully someone from whmcs will step in with clarifications

[Mytihost]

add this line to your configuration.php it will go back to normal behavior

$allow_adminarea_invoice_mutation = true;