Nextcloud is available in the Fedora repositories.
FAQ 1: I see it. I want it…I really want it… but then it says I can’t get it!!!
So, if you find that you see NextCloud in the repository but you cannot seem to install this, you could upgrade CentOS and make sure, as usual, your dependencies are all met. You know what I’m sayin’.
Use the SCL to get PHP 5.6+
yum install epel-release
yum install centos-release-scl
yum install nextcloud