Published by Matt Gemmell.
Hmm. It’s taken 4 years for me to realise that iCal Birthday Shifter shares an acronym with Irritable Bowel Syndrome. In any case, this minor update is for the former, fixing a crasher with nil-titled calendars (usually Groups; thanks to Adrian Kosmaczewski for the heads-up) and now ordering the calendars the same way as iCal instead of just alphabetically.