Add missing task properties

  • Ahoj and moin,
    could you please add missing properties like categories to your implementation of tasks in ical4android?

    The feature is also requested from a user of the Tasks Android app. I use the app myself and miss the categories in my other apps (Nextcloud for example). As I looked up the iCalendar specification I saw that the optional properies and those from RFC 7896 are not implemented yet, I would be very grateful if you could add (most of) them.

    Thank you in advance, keep up the good work. I use some Bitfire Apps from F-Droid for years now.


  • I, too, would greatly appreciate this!

  • This would be an awesome feature, that doesn't seem to be hard to implement. Please consider adding support for categories!

  • Is this being worked on? Please?

  • developer

    As far as I know, OpenTasks doesn't support categories in the UI yet:

    Do you know whether the backend supports categories and whether its usable or whether the UI also support categories?

  • I'm mainly asking for the Android App "Tasks", which uses ical4android to sync using Caldav, and already supports categories in the UI. See

  • Any updates on this? Anything I can do to help?

  • developer

    @Bob9 It's very complicated.

    1. These properties would ideally be implemented in ical4j, because standard properties should be in ical4j and shouldn't require custom (extended) properties in ical4android. So, you could write a patch to get those properties into ical4j (current ical4j version: 3.x).
    2. Next problem: This would have to be backported to ical4j 2.x, because ical4j 3.x requires Java 8, which is only available at Android 7+, while DAVdroid is for Android 4.4+ and we don't want to raise the minimum API level to Android 7 yet. So, you could make sure that those properties are available in ical4j 2.x, too. (Alternatively, you could play around to get ical4j 3.x working on Android 4.4+ with parts of the Java 8 API on older Android versions – this would be an ideal solution because ical4j 3.x is the future, but it it will be cumbersome.)
    3. Then those properties would have to be implemented in the ical4android Event/Task classes. This should be quite easy.
    4. To allow DAVdroid to use those properties, they should also be handled by AndroidEvent/AndroidTask, so this should be implemented too.

    At the moment, I don't have time for all of this, but if you want to write patches, please don't hesitate 🙂