Upgrade to v1.5.5 gives warning on all posts

I got the same issu

Is this with the new preference checked or unchecked and is the calendar coloring correct?

Can we just confirm that deactivating the plugin makes the error go away. I don’t see this on my test installation.

Sorry, but I don’t understand what you mean with “new preference”.
There is no colors in the calendar.
Deactivating the plugin makes the error go away.

Revert back to version 1.5 or wait till tonight when I can fix this in the next update. Sorry for the inconvenience.

Let me know if v1.5.6 fixes this issue. Thanks.

I just installed V1.5.6.
Everything seems OK.
Thank’s for help and reactivity.

Yes, v1.5.6 has fixed the issue for me too.

Many thanks for your quick response Andy!