Some ics files (eg: a zimbra file) I have encountered have the TZID enclosed in quotes.
The usual use (google calendar etc) is:
The spec examples do not show quotes and the quotes in the terminology definition are not I think meant to be included in the data. However this is relatively easy to deal with, so the next version of the plugin > 2.9.4 will cope with these.
Please note that the plugin currently ignores the VTIMEZONE in the ics file and uses the php database timezone.
The plugin will also not cope with the following yet (I have not yet encountered an ics file with it’s own timezone identifiers yet!):
fictitious globally unique time zone identifier example: