Frequently Asked Questions

ICSdroid is in some ways similar to DAVdroid (for instance, it relies on the Android sync framework to do its work and is built on the same libraries). So, having a look at the DAVdroid FAQ might give useful ideas.

[Xiaomi, Sony etc.] Synchronization never starts. How to fix it?

If the synchronization is not run automatically or the sync interval is always set to “manual”, please see DAVdroid FAQ: Automatic synchronization is not run as expected (just replace DAVdroid by ICSdroid).

How can I set the sync interval for a certain subscription?

We have intentionally avoided per-resource sync intervals to keep things simple. Just set the global sync interval to the shortest required period of all your subscriptions.

Does ICSdroid support two-way sync?

ICSdroid’s scope is to

  • fetch iCalendar resources at regular intervals,
  • write the contents of each iCalendar resource into a local read-only calendar.

Nearly all iCalendar HTTP(S) URLs are read-only. Most often, they are not even files, but dynamically generated by some script, so there’s no way how ICSdroid could update these calendars.

To update an iCalendar via HTTP(S), the server would have to support WebDAV. However, this method would still have some limitations. So, another protocol based on WebDAV has been designed: CalDAV. It supports two-way synchronization and is quite sophisticated.

To use two-way synchronization, please use CalDAV and DAVdroid instead of plain HTTP(S) resources with ICSdroid.

Does ICSdroid fetch all calendars at every sync?

For HTTP(S) resources, ICSdroid uses ETag / If-None-Match and Last-Modified / If-Modified-Since to avoid repeated downloading of unchanged data.

When processing VEVENTs, ICSdroid uses the LAST-MODIFIED property to check whether a resource (identified by an UID) has changed. Only changed resources will be updated in the calendar.

How can I subscribe to a shared iCloud calendar?

In iCloud, you can share a public calendar with anyone.

If you do so, you get a Webcal URL. Just enter this Webcal URL into ICSdroid and you’re subscribed to this public calendar!

How can I subscribe to a shared Google Calendar?

  1. Log in to Google Calendar.
  2. Share the calendar for public access.
  3. Get the iCal URL in calendar details (calendar URL / iCal). It looks like this: https:// calendar.google.com/calendar/ical/your@account/public/basic.ics
  4. Add the URL to ICSdroid.
  5. Ready! Your calendar will be synchronized.