Microsoft said they will release Windows 8.1 officially on October 17, with full retail availability on the 18th. The same date is also for Windows Server 2012 R2.
Between the Sheets — Excel podcast episode 31: Excel’s secret DATEDIF function
A quick and simple way of finding the number of days, months or years between two dates is Excel’s secret DATEDIF function. When you type it in a worksheet, there’s no popup syntax help to indicate the function exists.