Since this is a legacy patch, you won't find it on official modern launchers like Steam or GOG (which come pre-patched to 1.0006). You can find it on:
Look under the "Shadow of Chernobyl" patches section. 3. Installation Tips Since this is a legacy patch, you won't
A tiny handful of "ancient" mods from 2007 only work on this version. Since this is a legacy patch