NOTE: I just tried the trainer 13.1 b12 on current version 7 days to die Version v13.8 and the trainer works perfect for me. just make sure you run game WITOUT VAC (anti cheat program). I went to steam folder directory of game and create copy to desktop of the one that does NOT say 7daystodie VAC (that one is anti-cheat) and run it as admin and it seems to work (all options).
PS I said this before but it was never added as a note, in order to have inf stamina work drink or eat something Example beer, that effects stamina then you well have inf stamina.
This is for Steam version: Today I was having issues, I shut game down closed trainer, but for some reason after restarting game, trainer i was having issues, and I found solution.
1. Quit Game
2. Close trainer.
3. Restart Steam (Exit and relaunch steam).