Downloads for GTA 5 Redux available below.
GTA 5 Redux is single player only. ScriptHookV will prevent you from playing online if you try, this will prevent you accidently getting banned.
Full download of GTA 5 Redux
Torrent file for GTA5_REDUX_V1.2.1.zip
Hotfix updates ALL older versions to v1.3
Once you have downloaded ensure you use the available installation guide to correctly install GTA5 Redux.