How can I edit a customer invoice

[WHMCS John]

Hi all,

Thanks very much for your feedback on the invoice immutability and credit/debit notes implementation in v9.0.

We heard you loud and clear, and I'm pleased to say that in v9.1 we have implemented an admin-configurable Invoice Immutability setting. You can enforce invoice immutability, relax it while keeping billing notes, or turn it off entirely.

For more information check out our release highlights, try it out yourselves, and share your feedback in the v9.1 Beta Discussion Board

[LittleCreek]

6 hours ago, WHMCS John said:

Hi all,

Thanks very much for your feedback on the invoice immutability and credit/debit notes implementation in v9.0.

We heard you loud and clear, and I'm pleased to say that in v9.1 we have implemented an admin-configurable Invoice Immutability setting. You can enforce invoice immutability, relax it while keeping billing notes, or turn it off entirely.

For more information check out our release highlights, try it out yourselves, and share your feedback in the v9.1 Beta Discussion Board

Thanks so much John. 

[LMG]

7 hours ago, WHMCS John said:

Hi all,

Thanks very much for your feedback on the invoice immutability and credit/debit notes implementation in v9.0.

We heard you loud and clear, and I'm pleased to say that in v9.1 we have implemented an admin-configurable Invoice Immutability setting. You can enforce invoice immutability, relax it while keeping billing notes, or turn it off entirely.

For more information check out our release highlights, try it out yourselves, and share your feedback in the v9.1 Beta Discussion Board

Thank You!!

[robinson12]

The invoice immutability change definitely makes simple corrections more complicated. I can understand keeping an audit trail, but having an easy way to issue a corrected invoice without manually rebuilding everything would make the process much smoother.

[Patty]

That's great news! It should be optional indeed! Thanks, John! 🙌

[Eugene]

On 10/7/2026 at 5:40 PM, WHMCS John said:

Hi all,

Thanks very much for your feedback on the invoice immutability and credit/debit notes implementation in v9.0.

We heard you loud and clear, and I'm pleased to say that in v9.1 we have implemented an admin-configurable Invoice Immutability setting. You can enforce invoice immutability, relax it while keeping billing notes, or turn it off entirely.

For more information check out our release highlights, try it out yourselves, and share your feedback in the v9.1 Beta Discussion Board

woo, thank you so much 🙂

[slim]

Ok, so today was the first time I tried WHMCS 9.x - I avoided upgrading due to the reported issues.

In my dev install of WHMCS 9.1 The first thing I did was try to edit an unpaid invoice - and found there was zero ability to delete a product, change a price - nothing.

Unless im missing somthing, its unworkable in the current form without disabling the feature entirely. Providing a disable feature in the admin area and calling it 9.1 isnt going to cut it?

[Damo]

It should be an admin option based on this 

https://docs.whmcs.com/releases/9-1/9-1-release-notes/

https://docs.whmcs.com/9-1/system/general-settings/general-settings-invoices/#invoice-immutability

Edited 3 hours ago by Damo

[slim]

I get hat, but WHMCS only added that after significant backlash - and all it does is provide previous functionality, and a warning.

 

Using WHMCS with the invoice immutability option set as recommended makes it impossible to work with.

[Damo]

Absolutely after backlash. Enough so that 8.x remained. 

'Recommended' does not mean best suited. 

We did the 9 upgrade and it's been an admin nightmare for billing. We disabled it early with the config setting but it's been a mess. 
 

We will be doing full disable once GA.