Thanks goes to Altere, Zip & ryan - I've come up with this mis.service file which *seems* to be working:

[Unit]
Description=Mystic Internet Server
After=network.target
StartLimitIntervalSec=0

[Service]
Type=forking
User=pi
Environment="mysticbbs=/home/pi/mystic"
WorkingDirectory=/home/pi/mystic
ExecStartPre=/home/pi/mystic/mis poll killbusy all ExecStart=/home/pi/mystic/mis daemon
PIDFile=/home/pi/mystic/semaphore/mis.bsy
ExecStop=/home/pi/mystic/mis shutdown
ExecStopPost=/home/pi/mystic/mis poll killbusy all
Restart=always
RestartSec=1

[Install]
WantedBy=multi-user.target


Does anyone have any comments or critiques?

Jay

--- Mystic BBS v1.12 A47 2020/11/23 (Raspberry Pi/32)
* Origin: Northern Realms (21:3/110)