If you downloaded this from an unofficial source, ensure you scan it for malware, as ".zip" files with version strings are frequently used as wrappers for unwanted software.
Version 4.2.0 specifically addressed stability and multiplayer synchronization. Detailed notes are hosted on the World of Emergency official forums. 2. Research and Serious Games
The Greek prefix "Αρχείο:" (Archive) suggests you may have found this on a Greek file-sharing or community forum (like PC-Gr or similar).