OK - it sounds feasible and would need to be done entirely in JavaScript. Unfortunately, at the moment, I don't really have the time to work on this.
If you want to give it a try, I'd be happy to give you some guidance. If not, it's going to take a while, I'm afraid.

Yes, this is exactly what I meant.

Could you be a bit more specific with what you mean? What exactly should the setting prevent/disable/disallow?

Thanks for the report. I do not use Google calendar, so I never had the necessity to implement it (I only sync against Nextcloud).

While this works in an action plugin when registering the DOKUWIKI_STARTED event, the configuration manager does not reflect the changes - IMHO this is misleading. It should be possible to save the changes using config plugin's config manager classes - I'll investigate that.

$conf is global. You can change it from your plugin.

As far as I know, a plugin cannot overwrite core settings, only plugin settings. As these are core settings, those changes have to be made manually. However, even if it was possible to change the settings, I would prefer not to change settings automatically.

OK, I can see the problem with the datepicker in bureaucracy now. This seems to be a "feature" of the underlying fullcalendar.js library, though. I'll need to investigate that a bit further.

Thanks for your comment, much appreciated! It should be fixed now, would you mind having a look again?

Yes, I had the problem with 2017-02-19e and the current hg checkout of your plugin.

Thanks for the report. I cannot reproduce this on 2017-02-29e, the interface language of davcal follows DokuWiki's language for de, en, fr and nl. There is indeed a bug regarding datetimepicker which is always English (easy fix).

Of course this breaks the localization of the calendar view itself.

Perfect now it works again :) I thought i made a mistake.

No problem, I introduced a nice regression - I should definitely do more regression testing before pushing updates!
Anyway, please try the latest update published just now. The problem was/is the "C:" in <C:calendar-data> which confused the XML parser - I fixed it in 447fc5d456c1.

I'm sorry to hesitate you again.
Today i was working on the dokuwiki and recognised, that the plugin still dont work.
After that i saw the update for webdav
I updated the webdav plugin but nothing changed.

OK, I'm glad you got it working. I'm pushing an update anyway just now, since you discovered a bug with this broken XML tag.

It works now!
I updated davical from version 1.1.3 to 1.1.5 about backport package made a resync and now I see the data.
So I guess there where changes made for debian stretch.

Thanks for the quick response. Obvisily nothing changed i deleted brwoser cache etc.
Do you need access to my system?

OK, could you try the following:
In function clean_response (helper.php:1364), add as first line of the function:

$response = preg_replace('/xmlns[^=]*="[^"]*"/i', '', $response);

This might fix it, if not, we need to find another solution.

Thanks, that is the relevant part. The function clean_response messes the response up when davical is used (I only test against Sabre/DAV resp. NextCloud). It might take a bit until I come up with a solution, but I'll make that a high priority task.

This is helpful, although webdavclient doesn't seem to log the raw response. There seems to be an empty tag <''> which is closed by </multistatus> and that probably confuses simplexml_load_string().
Could you add the following line in helper.php on line 1126 (right before $response = $this->clean_response(...))

Hm, seems to be related to davical. Unfortunately, I can't test this since I do not have a davical installation.
Please enable debug logging and force a sync. Then, you should be able to see some XML output in the debug log - be aware that your calendar data is included here!

Actual i found this at the apache error.log

What exactly are you trying to achieve? You want to synchronise your DokuWiki calendar to davical, right?
Did you configure WebDAV connections in the Admin section? If so, were you able to display the available calendars?

I don't really understand your question. What I've understood is that a user should have read/write access to a calendar when he's logged in to DokuWiki. This is the exact behaviour. Put simply: