Set in Duration for New Icon Indicis SharePoint

To Set the Duration for New icon in SharePoint (ex quibus constare potest, deinde ad novum items indicator) access the SharePoint WebApplication object and set the value for DaysToShowNewIndicator.

SPWebApplication WebApp = SPWebApplication.Lookup(new
Uri(WebAppURL.Text));

WebApp.DaysToShowNewIndicator = 3;

WebApp.Update();