You'll want to check out the Help document for platform-specific instructions and troubleshooting steps. * Some caveats and additional steps may be required on Mac. see the Mac section of the HELP ...

Keep your Pavlov mods from Mod.io up to date on Windows. Only tested on Windows with the Steam game. Seems to work well for map and non-map mods. Primary Features: Detect and update out-of-date maps ...