The opencloud package to use. OpenCloud has 2 release cycles, explained on https://docs.opencloud.eu/docs/admin/resources/lifecycle.
Use pkgs.opencloud package for the rolling release (every 3 weeks). Use pkgs.opencloud-production package for the production release (about every 6 months).
OpenCloud does not support downgrading existing installations. Switching from pkgs.opencloud to pkgs.opencloud-production is considered a downgrade.