Thank you once again, eschwartz
Running `sudo crontab -l`gives me the following:
0 6 * * 5 /usr/bin/calibre-upgrade.sh > /dev/null 2>&1
Having looked at that output in man 5 crontab, it would appear to indicate that calibre-upgrade.sh will run at 6 a.m. every Friday and therefore presumably any stable release of calibre would be automatically installed thereby on a Friday at 6 a.m., if I accurately comprehend what this intends to achieve.
