ModIV is a payable upgrade, available from SC’s webshop (198€).
*Scope software v5 required.
*comes with ~100 new modules, some bugfixed Mod2/III modules, and a new modular shell.
*the ModIV shell is basically the same as in ModIII (except some graphical changes), and comes in the usual 2In/4Out and 8In/8Out varieties.
*ModIV modules can be loaded into Mod2/III shell.
*ModIV module listing: see here.