Hi there!
I’ve got a problem migrating from OC 9.1 to NC 9. I’ve done that changing NC version in config.php (how it was described here) and everything went fine except the Calendar app.
It doesn’t show up my calendars (neither contact_birthdays nor my custom added one). I just get this in the list of calendars.
Nothing useful in the httpd error log.
Please help 
The calendars are accessable via CalDav though
I had the same problem after crossgrading, but only on the Linux version of Chrome - when I remember it right.
After an browser update everything worked well again.
Haha! Thanks, it’s true. In my case it’s Pale Moon browser misbehaving. In Firefox everything’s fine.
It is a good question whether it’s a Nc or browser bug …whatever it is it should be filed to the correct bug system (Nc or affected browser).
IMHO the way to decide where the issue stems from is to check it for W3C validity:
- if the output is not W3C valid, it’s the website/webapp’s issue,
- if it’s 100% W3C compliant, it’s an obvious browser bug and should be filed there.
That’s what standards and validators are there for 
/me totally not looking forward to seeing the world return to back to the “best viewed in IE x.y” / “best viewed in Netscape z.w” dark ages.