CWS 58 requires a specific minimum System Software version on your Fiery Server. Downloading the wrong regional build (even if verified) can cause a "Version Mismatch" error. Use the Fiery Configure tool to auto-detect which build your server needs.
To access the legacy downloads, you generally need a registered account. If you are a service technician or a print shop owner, you likely have credentials.
CWS_5.8.2.51.exe or similar.There is no single "magic button" for legacy software, but there is only one trusted source: EFI (Electronics For Imaging).