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fanf

Apple calendar apps amplifying .ics VALARM ACTION:EMAIL

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8th May 2016 | 15:30

This took me hours to debug yesterday so I thought an article would be a good idea.

The vexation

My phone was sending email notifications for events in our shared calendar.

Some of my Macs were trying and failing to send similar email notifications. (Mac OS Mail knows about some of my accounts but it doesn't know the passwords because I don't entirely trust the keychain.)

The confusion

There is no user interface for email notifications in Apple's calendar apps.

  • They do not allow you to create events with email notifications.
  • They do not show the fact that an event (created by another client) has an email notification configured.
  • They do not have a preferences setting to control email notifications.

The escalation

It seems that if you have a shared calendar containing an event with an email notification, each of your Apple devices which have this calendar will separately try to send their own duplicate copy of the notification email.

(I dread to think what would happen in an office environment!)

The explanation

I couldn't get a CalDAV client to talk to Fastmail's CalDAV service in a useful way. I managed to work out what was going on by exporting a .ics file and looking at the contents.

The VEVENT clause saying ACTION:EMAIL was immediately obvious towards the end of the file.

The solution

Sadly I don't know of a way to stop them from doing this other than to avoid using email notification on calendar events.

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Comments {7}

Rachel Coleman

from: rmc28
date: 8th May 2016 21:24 (UTC)

As a result of this I have coughed up the money to access the Fastmail CalDAV service and will work on a) getting the calendar app on my phone working b)turning off email notifications on all the shared calendar items

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Tony Finch

from: fanf
date: 9th May 2016 08:10 (UTC)

Yeah sucks :-/ I should have said I don't know if this is an Apple bug or how .ics is supposed to work - I didn't notice any hints on the ACTION:EMAIL about who should send it...

The Fastmail app does mail and calendaring and seems pretty nice.

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Rachel Coleman

from: rmc28
date: 9th May 2016 09:15 (UTC)

I use it for calendaring already, but only the home calendars, I haven't tried to make it talk to my work calendar yet (which is one thing the native app does).

The mail UI irritates me, so I usually only use it if I need to search. For reading/culling email, I much prefer K-9 Mail, but its search isn't as good.

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Ian Eiloart

from: IanEiloart
date: 9th May 2016 15:02 (UTC)

You'd think that any answer other than "the server" would be wrong here!

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And there's more...

from: anonymous
date: 9th May 2016 07:17 (UTC)

If a calendar invite has multiple notifications (e.g. at 15 & 5 minutes before the event) Apple's calendar handles this as two separate calendar entries.

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Tony Finch

Re: And there's more...

from: fanf
date: 9th May 2016 08:16 (UTC)

Weird. Apple's calendar apps support up to two notifications, and the problem events had both email and audio alerts and appeared as one event covering both alerts.

I totally believe that this kind of interop problem exists, but it must be a bit more complicated than you describe.

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Rachel Coleman

Re: And there's more...

from: rmc28
date: 9th May 2016 09:15 (UTC)

Most of the affected calendar items have 1 notification time.

(I'm the person who sets them up, and wants the email notifications ...)

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