There may be a SMP's bug on installation. See wiki.
REQUIRES SMP 1.6.1 (mod version attached has some improvements by marc23)
See full changelog here.
[3.5.0] - 2023-11-28
Added
- Buttons bar: added compatibility with headless mode (for other buttons).
Changed
- Helpers: updated helpers.
- Improved error messages about features not working related to OS checks (at startup) with tips and warnings.