Calendar migration from 8.2.11 to 10.0.10 without upgrading ownCloud itself



I have two servers running ownCloud. One of them is running version 8.2.11, the other one is running the latest version, 10.0.10.

Both are used in a work environment with a little over 100 users.
I need to migrate the caldav calendars from the 8.2.11 ownCloud server to the 10.0.10 ownCloud server.

I can think of three ways of doing this:

  1. upgrade the 8.2.11 ownCloud server (or a copy of it) step-by-step to the latest version. However, I don’t feel strongly about this option, as I’m simply looking for a way to migrate the calendars. I don’t want to migrate the entire server setup.
  2. Copy the MySQL database entries. However, it is my understanding that the MySQL database structure for ownCloud changes between major versions, and the calendar entries have a different format in 8.2.11 and 10.0.10.
  3. manually log-in on every user account, download/export the calendars, and then import them again on the new server. However, this option won’t work well. Even if I had the time and patience to do it, I cannot nilly-willy reset people’s LDAP passwords to log-in on their accounts. It’s not an elegant solution. But if there was an option to do this in an automated fashion, without having to actually log-in on people’s accounts, then I think this would be the way to go.

My question is: Is there a good, effective way to only migrate the calendars and nothing else? Maybe a command line option, or a script? I already checked out the occ command, but there was nothing like it in there.

Server configuration

Operating system:
Debian 7 and Ubuntu 18.04

Web server:
Apache 2.2 and Apache 2.4


PHP version:
PHP 5 and PHP 7

ownCloud version: (see ownCloud admin page)
8.2.11 and 10.0.10

Updated from an older ownCloud or fresh install:
Updated, and fresh install

Where did you install ownCloud from:
Unknown, and from the package repository


This will probably not be a big help, but at least for exporting you don‘t need the users passwords when using the calcardbackup script with option -f (the text in this thread is quite outdated - the at GitHub is up to date): Calcardbackup: bash script to backup ownCloud calendars and addressbooks as *.ics/*.vcf files