Sabre exception - Unsupported version '1.4'

My calendar was working great for weeks, but since last week it is not working anymore: no more synchronization with mobile clients and no display on the Nextcloud web client.
in the log I can see a fatal error on webdav:
> Exception: {“Message”:"HTTP/1.1 400 Unsupported version ‘1.4’\n on line

 1, column 
 [internal function]: 
 call_user_func_array(Array, Array)\n#2 
 Sabre\\Event\\EventEmitter->emit('method:PROPFIND', Array)\n#3 

Any idea? Thanks !

Have you, or your hosting provider made any changes to the hosting environment? Has anything changed in Nextcloud or applications?

I’m self-hosted on a Synology server. And last week, My server has been updated with this changes:

Fixed an issue where SHA may fail to set SNMP UPS.
Fixed an issue where Synology E10G15-F1 NIC may disconnect under certain circumstances.
Fixed an issue where Full File Clone via VMware VAAI could cause NFS protocol to act abnormally under certain circumstances.
Fixed an issue where the page at Control Pannel > Domain/LDAP does not respond.
Fixed an issue where Snapshot Replication could not open normally in certain timezones.
Fixed multiple security vulnerabilities regarding curl module (CVE-2016-5419, CVE-2016-5420, CVE-2016-5421).Upgraded OpenSSL to 1.0.2j to address multiple vulnerabilities (CVE-2016-6304, CVE-2016-2183, CVE-2016-6303, CVE-2016-6302, CVE-2016-2182, CVE-2016-2180, CVE-2016-2177, CVE-2016-2178, CVE-2016-2179, CVE-2016-2181, CVE-2016-6306 and CVE-2016-7052).
Fixed an issue where system resources are not released properly after QuickConnect is enabled.
Fixed an issue where file indexing is not triggered when files are uploaded through Samba protocol.

I thought it could be the curl update (as a lot of webDav problem seems to come from curl), but how to verify, and how to fix it?
What is your analysis?

If you’re getting updates from Synology, then I would contact them for support. It appears something done from the update caused the issue.

You can also try reinstalling Nextcloud to see if that resolves it.

@tflidd @LukasReschke before he reinstalls, any experience?

Which version of NC is installed? I don’t see any problem with one of the updates.

Does the calendar still work with a completely new user? Yes -> could be a problem with an existing entry (should not happen either), no-> general problem. Was the webserver configuration changed ruing update (activation of mod_security, …)?

CalDAV is part of the core, so you can report the issue there if you are running a current version->

I’m under version Nextcloud 10.0.1 (production).
I created a new user, and the agenda is still loading. So it is a general problem. Difficult to say if the webserver configuration has been changed recently as I don’t know exactly what has been done by the last Synology update.

@tflidd do you say that with the last Synology update you don’t have any problem on your own?

I’ve post a question about that to the Synology support.

I don’t use Synology, it’s only based on the changelog you posted that there is nothing I would identify being the problem. But there might be other changes as well.

Ok, I installed a new instance of Nextcloud on my Synology server. Then copy the calendar databases from the original to this new copy.
And it works. So it is not the webserver, and it is not the calendar database.

I marked the new install as solution. If you experience that again, please open an issue on github to figure out the underlying problem.