Thank you for your feedback on the OOF feature. At this time, we have no plans to add functionality to OOF. However, we reevaluate requests every quarter and will reach out if priorities change. Please keep the feedback coming as it is critical for our longer-term planning.
https://nintex.uservoice.com/forums/932680-k2-cloud/suggestions/42608566-customizable-out-of-office-notification-emails
and
https://nintex.uservoice.com/forums/932680-k2-cloud/suggestions/42433018-out-of-office-date-range