Ah, didn’t do anything like that yet, because I use the posteo-calendar. Does it mean I will have two calendars now, 1 posteo 1 thunderbird?
thanks also for the instruction (die auf deutsch) I will follow that now.
OK that will be the next thing I try. I ended up using DAVdroid, because that is what I found in the posteo info on how to sync calendar (and contacts) between posteo and FP.
seems like there is still quite a task ahead of me… 
If you follow the instructions from Posteo on how to set up the calendar in Thunderbird, the calendar will be synced from Lightning to Posteo and back. Just make sure you always use the synced calendar in Thunderbird if you want your appointment to be synced. This way you can have the same calendar on all of your devices. 
I’ve read somewhere that because of permission legacy in Android, you need to install Tasks before DAVdroid. So if you have done it the other way round, you need to uninstall DAVdroid and install it again to let Android know that Tasks has tasks for DAVdroid. 
? still don’t get it.
I don’t really want the calendar to be in thunderbird, I am happy with using it in posteo and on FP, don’t need a 3rd calendar location. But I seem to need thunderbird / lightning to sync the tasks, so is that only possible with calendar in thunderbird as well?.
Yes I read that too, so when I started with tasks I deinstalled DAVdroid and then installed it again.
Ohh, sorry, I got you wrong there. So if you don’t need the calendar or tasks to be shown in Thunderbird there is not need at all to use Lightning/Thunderbird. As you do want to sync tasks, I personally recommend using Thunderbird because it’s usually very convenient. There might be other ways but in Thunderbird you could actually have your e-mails, calendar AND tasks in one place without having to open the browser and logging in at Posteo. Of course that is a question of personal preference 
If you want to view your tasks on a computer you will definitely need a client that syncs the calendar though because tasks are always synced with the calendar file and cannot be viewed in the Posteo web interface.
I hope this helps a litte 
Just out of curiosity, have you solved your problem?
Hi and so sorry I did not post earlier here (I thought I did but apparently I didn’t).
well I am using the mixture you all suggested of these many calendars - so I have the posteo calendar, syncing it to thunderbird, where I also see the tasks, which I also have on the FP. (although I don’t get the same categories for the tasks on thunderbird as on FP)
And I have the contacts / addresses on posteo and FP as well.
I got a second chance to do all this since a back-up crashed my tasks and the different calendars - so I will be really getting good at this. 
Just to mention here as well that for some unknown reason the syncing of tasks is not possible any more (last time it worked was nearly a week ago):
Any ideas what I could try to get it syncing again?
can you provide a logcat in order to see if there is some issue during synchronizing?
Please remember to check for personal data and remove them before publishing system logs extracts
bye! 
In den Einstellungen zu einem Account kannst du ein Fehlerprotokoll auf die SD-Karte speichern lassen:
You can log to SD card in the settings of an account:
@DjDas @Stefan
unfortunately I cannot switch on the protocol. When I try to move the switch to AN I get a warning, and when I click OK the warning is repeated again and again but nothing else.
For logcat you simply need adb or an app like OsMonitor in order to get the system log messages and then you can copy/paste them in a text file.
Bye!
You are right! :woot: I’m sure this is unexpected behaviour. Somebody should probably tell them…
Anyways, you should probably head to the DavDroid Forums. I had a problem once and they are quite eager to help.
Update:
It is a bit weird, because apparently as I have tried out a few times now, the tasks ARE synced between FP1 (via posteo) and thunderbird in both directions.
Only the syncocol - as in the screenshot I posted before - says that the last sync is from Nov 18 and that there are problems.
I saw two Davdroid updates on F-Droid in last days, maybe they solved some sync issue?
@DjDas thanks for the tip!
I don’t get an update notification for Davdroid on my f-droid app at the moment (but instead, for 4 apps, 2 of which I haven’t installed on my FP or at least did not see on the app-list. Have deinstalled them now via f-droid app).
So I’ll wait a couple more days and if I don’t get a notif. I’ll deinstall and install Davdroid again…
---- Oh, and I see the old problem with iFixit still exists: there is an update notif, but I cannot update because of wrong key version, I have to deinstall. But: it is not possible to deinstall. Weird!
Update:
without me having done anything everything is alright again now (look at syncocol):
Davdroid: it’s magic 
- champagne for all!
Regarding iFixit this is a known problem due to the fact this is installed as a system app; you can disable notifications for it by selecting “Ignore all updates” in the menu inside its application page in F-Droid.
If you would like to update it, you can use SystemAppMover (you need also Busybox, which you can find on PlayStore) to convert it to a normal app and then uninstall it, after you can install it from F-Droid as normal apps
