[otrs] Sort Queue View by Last Update from Customer

I've seen a number of threads asking about sorting the queue view or dashboard by Last Update, but all of the solutions I found apply to older versions. Any hints as to how to do this? I was thinking about using TicketFreeTime, priority, Ticket::Frontend::AgentTicketQueue###SortBy::Default:--> something other than Age, DashboardBackend###0130-TicketOpen: (currently Age, tried setting to Change, Update, LastUpdate, etc.)... I know change_time is stored in the db, just a matter of getting access to that... I'm not 100% sure if LastUpdate is the terminology, but I'd love to sort by the time since a customer last emailed. thanks! -Scott