Extra commands are needed in addition to upgrading packages.
pkg upgrade -f openhab openhab-addons
service openhab stop
mv /var/db/openhab/userdata/cache /var/db/openhab/userdata/cache.$(date '+%Y%m%d')
mv /var/db/openhab/userdata/tmp /var/db/openhab/userdata/tmp.$(date '+%Y%m%d')
mv /var/db/openhab/userdata/etc /var/db/openhab/userdata/etc.$(date '+%Y%m%d')
install -d -o openhab -g openhab /var/db/openhab/userdata/cache
install -d -o openhab -g openhab /var/db/openhab/userdata/tmp
cp -R /usr/local/share/openhab/etc /var/db/openhab/userdata/
chown -R openhab:openhab /var/db/openhab/userdata/etc/
reboot