Review for Provider for Google Calendar by Radu Mitroi
Rated 4 out of 5 stars
Add-on works as advertised, but there's a bug: when setting a reminder from the drop down list, it is saved. But when setting a Custom reminder, it is reverted to the default (0 minutes) on saving.
This review is for a previous version of the add-on (3.1).I'd suggest contacting support on this issue. If the reminder is more than 28 days before the event this may be a server side limitation
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