The HSB4-serverupdate.zip file you have requested: Modifications / Hidden Source / Hidden: Source Beta 4 Server Update - 23.96mb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
In "The Hidden", players choose the role of either a near invisible killer, Subject 617, or one member of an Intercept squad who have to capture him, I.R.I.S. In the simple but challenging gameplay of an 'one against all'? mode, Subject 617 creeps/sn This is the dedicated server (win32 + linux) update for Hidden: Source, it should be unpacked over an existing Beta 3 install - backing up of config files is recommended - though there are new cvars as explained in server.cfg.