ST4 focused on making the interface more "thoughtful" and efficient rather than just adding "wow factor" features. It allows you to maintain surface relationships and adjust them on-the-fly, which is critical for complex 3D modeling.
Official downloads for older versions like ST4 are typically managed through the Siemens Support Center . siemens solid edge st4 x86 x64 download work pc
If you lost your original ST4 media, contact Siemens directly with your old license number. They frequently provide download links for paid-up perpetual licenses. ST4 focused on making the interface more "thoughtful"