STK Components has a built-in table of leap seconds that includes every published leap second as of the time that particular version of STK Components was released. In addition, STK Components provides programmatic interfaces to add leap seconds via the same LeapSecond.dat file used by STK Desktop.
Which versions of STK Components include the June 30, 2015, leap second?
Starting with STK Components 2015r1, released January, 2015, the built-in leap second table includes the June 30, 2015, leap second.
What if I need to use a version of STK Components prior to 2015r1 and need it to account for the June 30, 2015, leap second?
You must include some code in your application to tell the older version of STK Components about the new leap second. The simplest way is to ingest the LeapSecond.dat file found at
https://ftp.agi.com/pub/STKData/Astro/LeapSecond.dat by using the LeapSecondFile class. The following code loads the updated leap second file, activates it in the current CalculationContext, and makes the current CalculationContext the default one for all new threads.
C# example:
LeapSecondsFacet leapSeconds = LeapSecondFile.ReadLeapSeconds(@"c:\path\to\LeapSecond.dat");
leapSeconds.UseInCurrentContext();
CalculationContext.DefaultForNewContexts = CalculationContext.Instance;
Java example:
LeapSecondsFacet leapSeconds = LeapSecondFile.readLeapSeconds("c:\\path\\to\\LeapSecond.dat");
leapSeconds.useInCurrentContext();
CalculationContext.setDefaultForNewContexts(CalculationContext.getInstance());
AGI recommends that you do this at the startup of your application, before any threads are created and before any other STK Components code is executed.
If you need to update STK or ODTK for the leap second, check out the article
How are STK and ODTK Earth Data Files Updated?