Qshutdown works in different OS and environments: Ubuntu, Kubuntu, Xubuntu, Ubuntu Budgie.
I tested in Linux Mint, the program works stable, I did not reveal any errors.
In the Settings you can change various values on your own:
Qshutdown will show a warning 3 times will remain less than 70 seconds to run the Event, which you can also cancel.
Note. When sending a request to shutdown command, the current session is not saved.
Installation latest version into Linux Mint:
May the Force be with you,
sudo add-apt-repository ppa:hakaishi/qshutdown sudo apt update sudo apt install qshutdown