Nextcloud is a free software platform with thousand of hundreds of install, millions of users and hundreds of developers. Nextcloud code repositories are available on github
Behind Nextcloud there is a for-profit software house offering enterprise version of it https://nextcloud.com. There are also many commercial providers available.
We choose Nextcloud as a base for Convivium because it's a well established software with a vibrant community of users and developers worldwide. Its core technologies are around since decades, cooked into a typical LAMP stack, which means: Linux as the default OS, Apache HTTP as the default webserver, MySQL as the default DB, PHP for scripting, all baked into the more recent web VUE.js framework. It is released under a free licence, Affero GPL 3.0
Our install has been performed on a GARR VM machine thanks to UNISI agreement with GARR, member of the Géant network
https://docs.nextcloud.com/server/latest/adminmanual/installation/exampleubuntu.html