You can check the Broadcom Support Portal for legacy downloads, though these typically require a registered account and may only go back a few versions.
If the official portal does not list it, community archives like Archive.org sometimes host original installers, but users should exercise extreme caution and verify MD5/SHA checksums for security. Key Features of VMware Fusion 4 vmware fusion 4 download
Finding an official download for version 4 is difficult today because the Broadcom Support Portal primarily hosts modern versions (Version 13 and newer). You can check the Broadcom Support Portal for