Hi Ajay,
Version 4.5 dates to 2015, and for a compiler that supports it, we can get that date via a command like:
echo | cpp -fopenmp -dM | grep OPENMP
That runs the preprocessor (on empty input) with -fopenmp, shows all predefined macros, and restricts to anything with OPENMP in the name.
Currently, only the macos_10.12_local and linux_fedora_28_shared packages (out of those distributed) seem to come with OpenMP 4.5.
If you want to build AFNI on your own, it isn't hard (especially on linux). What OS are you using?
- rick