BaseDate is a TDateTime property that indicates the initial date used for Time server calculations. When the BaseDate for the client and server are identical, and exceeds the value of DateTime, DateTime can contain values beyond the year 2035. 

Do not change BaseDate unless the Time server uses the same value for it's BaseDate. 

The default value for BaseDate is TIMEUDP_BASEDATE as assigned during initialization of the component. 

BaseDate is used calculating the value for DateTime using DateTimeCard, RoundTripDelay, and the timezone bias for the local machine. 

BaseDate may contain 0 (zero) when the cardinal date value for the time server represents the date and time value for: 

   12/30/1899 12:00

TIdTimeUDP.DateTime 

TIdTimeUDP..DateTimeCard 

TIdTimeUDP..RoundTripDelay