We are on WordPress 3.6. We started having My Calendar problems last night, version 2.2.7. First, all seemed OK on our main site but not on our phone/tablet derivative (dudamobile) site. The dudamobile glitch sorted out for awhile this AM. This afternoon, the main web site (www.bikewjw.org) had glitches in My Calendar, the details for entries would not close. This evening, I updated to My Calendar 2.2.9. Now it will not display at all, in either site. Other aspects of our site (mobile and regular) seem OK.
I saw no recent relevant discussion of this on the My Calendar thread.