SolidWorks macros (same as SolidWorks itself) are backward compatible. So they should work with newer versions without any change. Sometimes some minor fixes required such as fix the references but usually they are fully compatible.
You may also find this thread useful: Macros Troubleshooting: Issues And Resolutions
Thank you Artem. I will keep that link on file as I work on macros.
What reference issues have you noted?
I wrote a custom property macro for my previous company in 2003. They're still using it. The only thing I ever had to change for version compatibility reasons was when SW switched from 32 bit VBA to 64 bit VBA7, and that was because there were no database drivers for VBA7, not because of SW.