The ns_dedicated_server_patch_v3.1.3.zip file you have requested: Modifications / natural selection / v313 / Natural Selection v3.1.3 Server Patch - 2.1mb is not available. Perhaps try browsing all files for the game Half-Life and upload any files you want to share or are missing. This is the only information we could locate:
The NS team has just finished testing NS v3.1.3 which we are now making available to the public! This is a server-side patch, so only server-operators will need to download it (both Windows and linux are included). NS v3.1.3 changelogo Gorges o Natural Selection has released their v3.1.3 update patch, server-side only.