Nextcloud
From wiki
Prerequisite
Install
Add Repository
In order to get an up-to-date ownCloud, it is preferable to install it from the upstream repositories.
Use the following command to install the repository and its key, plus to configure pinning to use it as the default source
$ curl -s https://download.owncloud.org/download/repositories/stable/Debian_8.0/Release.key | sudo apt-key add -
OK
$ echo "deb http://download.owncloud.org/download/repositories/stable/Debian_8.0/ /" | sudo tee /etc/apt/sources.list.d/owncloud.list > /dev/null
$ sudo tee "/etc/apt/preferences.d/owncloud" > /dev/null << EOF
> Package: owncloud
> Pin: origin "download.owncloud.org"
> Pin-Priority: 995
> EOF
$ sudo apt update
Install
$ sudo apt install owncloud