This is an old release. You should use the latest version instead!
SMAPI 3.8 adds full support for Stardew Valley 1.5 (including split-screen multiplayer), and adds support for running the installer from within the game folder to auto-detect it (for cases where it's not detected correctly).
See the release highlights.
Requires Stardew Valley 1.5 or later on Linux/Mac/Windows.