Nextcloud is a free and open-source suite of client-server software for creating and using file hosting services. Self-hosted, open source software allows you maintain full control of your data. It provides for file synchronization between multiple clients, calendar synchronization via CalDav. contacts synchronization via CardDAV, photo galleries, and much more. COG - NextCloud includes: NextCloud Server, 64-bit Linux, the latest PHP 7, Nginx, MariaDB.