I don't thing nextcloud 12 is the issue here. Simple the old used "caldav" application and the connected AndroidCaldavSyncAdapater is not working anymore.
I've removed the users everywhere as well as the application. I've switched the phone to use the DAVDroid installable via F-Droid.
The setup is so easy I won't write a howto section here.
Just be fair and donate some money to DAVDroid since the application is working out of the box.
Just figured out that my calendars in thunderbird where not working anymore after the nextcloud 11.0.0.
A quick look and comparison I spotted the change, "caldav" changed to "dav" in the url.
Example needed?
I just migrated my installation from owncloud 9 to nextcloud 9.0.50.
Only one thing is not working, the notes application simple shows me an empty list of notes. beside that, it is more like a new theme.
At the moment we only support manual migrations from ownCloud 8.2 and 9.0 to Nextcloud 9.
To do that please follow the usual upgrading steps:
* Delete everything from the ownCloud folder except data and config
* Download the Nextcloud 9 release from https://nextcloud.com/install/43
* Put the files into the folder where the ownCloud files where before
* Trigger the update either via OCC or via web.
#make a backup of your database
#log into your server and cd to the owncloud path
#
#assuming your installation is in the directory "cloud"
./occ maintenance:repair
cd ..
wget https://download.nextcloud.com/server/releases/nextcloud-9.0.50.zip
unzip nextcloud-9.0.50.zip
cp -rv cloud/config nextcloud/
cp -rv cloud/data nextcloud/
mv cloud owncloud
mv nextcloud cloud
cd cloud
./occ upgrade
./occ app:list
#enable the apps you want
Update from 2016-06-26
I created a small upgrade.sh script. Here it is.
#!/bin/bash
####
# @author stev leibelt
# @since 2016-06-26
####
#begin of runtime environment validation
if [[ $# -lt 1 ]]; then
echo "invalid number of variables provided"
echo "upgrade.sh "
exit 1
fi
if [[ -d backup ]]; then
echo "backup directory sill exists"
exit 1
fi
#end of runtime environment validation
#begin of local runtime variables
LOCAL_CURRENT_DATE=$(date +'%Y-%m-%d')
LOCAL_URL_TO_THE_NEXT_VERSION="$1"
LOCAL_PUBLIC_BACKUP_PATH="public_$LOCAL_CURRENT_DATE"
#end of local runtime variables
#begin of downloading new version
wget $LOCAL_URL_TO_THE_NEXT_VERSION
unzip *.zip
#end of downloading new version
#begin of making backups
cd public
tar --ignore-failed-read -zcf "public.$LOCAL_CURRENT_DATE.tar.gz" public
./occ maintenance:singleuser --on
cd ../
mkdir backup
cp -rv public/config backup/
cp -rv public/data backup/
mv public $LOCAL_PUBLIC_BACKUP_PATH
#end of making backups
#begin of upgrade
mv nextcloud public
cp -rv backup/config public
cp -rv backup/data public
cd public
./occ upgrade
./occ maintenance:singleuser --off
echo "enable the apps you need with ./occ app:enable "
./occ app:list
#end of upgrade