This article also answers:


Can I send payment reminders to customers paying offline?

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Yes, you can remind your customers about their Payment Due invoices by checking the enabling the Enable offline dunning option under Settings >> Revenue recovery >> Dunning for offline payments. 


If you have Net D configured, the reminder emails will be sent after the configured number of days. 


More information here


Note: This feature is supported on the V1 & V2 emails.