The version number (1.5.2) mimics versioning seen in legitimate emulators (like older builds of PCSX2). However, because the software does not actually exist, the version number is arbitrary. The .zip extension suggests a compressed installer, but as noted above, the size is far too small to contain the necessary firmware emulation tools required for PS4 architecture.
To download PCSX4, simply click on the PCSX4-1.5.2r2-setup.zip file (58.64 MB) and follow these steps: Pcsx4-1.5.2r2-setup.zip 58.64 Mb
If you are looking to emulate PlayStation games, consider these alternatives: The version number (1