The error message is remarkably specific. It tells you exactly what is wrong:
ls -l /sbin/pfctl
cd /usr/src/sys/modules/pf make clean && make && make install kldunload pf kldload pf pf configuration incompatible with pf program version
Integrated these actions directly into the filter rules (e.g., match in all scrub (no-df) or pass out on em0 nat-to 1.2.3.4 ). The error message is remarkably specific
Output:
/etc/pf.conf: pfctl: pf configuration incompatible with pf program version pf configuration incompatible with pf program version