WCF Data Services 5.x is an updated bundle of client and server set of libraries for Microsoft .NET framework that ships as a default set when Visual Studio 2012 is installed. A detailed list of capabilities that are offered as part of WCF Data Services 5.0 is availablein the MSDN here
You can download WCF data service from the MSDN website WCF Data Services 5.0 for OData V3.
Microsoft has released many updates to the WCF Data Services since 5.0 primarily to introduce new features, fix bugs, and incorporate support for Visual Studio 2013. These updates are available as NuGet packages but developers are free to download the references from other sources as well.
The new out-of-the-box version of WCF Data Services is installed in the program files directory rather than with the reference assemblies. You can find the new assemblies in the following installation path on an x64 computer:
%programfiles(x86)%\Microsoft WCF Data Services\5.x\bin
The DateTimeOffset structure includes a DateTime value, together with an Offset property that defines the difference between the current DateTimeOffset instance's date and time and Coordinated Universal Time (UTC).
You can read more about date time offset in the MSDN website at DateTimeOffset.
A TimeSpan object represents a time interval (duration of time or elapsed time) that is measured as a positive or negative number of days, hours, minutes, seconds, and fractions of a second.
The TimeSpan structure can also be used to represent the time of day, but only if the time is unrelated to a particular date. Otherwise, the DateTime or DateTimeOffset structure should be used instead.
For more information about using the TimeSpan structure to reflect the time of day, see Choosing Between DateTime, DateTimeOffset, and TimeZoneInfo.