We have a own archive-backup-server where we store backups from all our services. (Nextcloud, files from file server,…)
We also want to add the backups from updraftPlus on this server. At the moment we solve it by copy the files to an FTP-Server and execute an rsync job on this server.
It would be great, if we can copy the files via rsync directly one day.
This idea was posted in UpdraftCentral - remote control plugin on October 26, 2017 by 
ft systems gmbh.
Interesting idea. Not easy to do in a way that’s widely compatible, as there are no native PHP rsync libraries (only ones that are wrappers onto /usr/bin/rsync). Let’s see if there’s more interest in this idea.