Task Due Date with Holidays into account

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We have a requirement where, in the workflow when is task is being created and due date set as say +1 days, customer wants to first check if the next day is a holiday or not.For some reason we cannot use RN SLA and this is a typical workflow based scenario.So please don't suggest me that : )

I know we don't have holiday concept in task plus there is no CPM which can be set.The only option that looks feasible to me is to have an add-ins (customization) created during task create which will check if the already set due date is a holiday then move it to next day etc