There are two levels of ExtendSim 10 definitions:
#include "v10 include file.h"
and some v10 compatible code; // note that this can use V10 functions that are not defined in V9 as v9 will ignore this
#include "v9 include file.h"
and some v9 compatible code;
if (GetExtendVersion(0) >= 1000.0)
do something that v10 needs (must use v9 compatible functions if you need to run this block in v9);
do something that v9 needs;