Allow 0.00 Transactions
in some cases, we need the option to add 0.00 transaction for 0.00 Invoices
1. in case invoice created and I want to give to this client month free / domain register / renew for free2. in case of fixing billing issues manually3. approval of free account / trail with invoice, when Product provisioning is invoice related4. in any other case we need to mark the invoice as Paid and run the related provisioning process, buy or renew domain, create or renew hosting account and any other provisioning account
now, In WHMCS v6.x it's not possible since there is new validation that block 0.00 Transaction
Please add some option in Setup -> General Settings -> Invoices that say "Enable 0.00 Transaction"
selection this option will disable this validation and allow to use it as it's was before this new validation.