Hi,
i’m having the same issue.
But it doesn’t work with my server.
I downloaded https://download.nextcloud.com/server/releases/nextcloud-16.0.9.zip renamed to nextcloud-16.0.0.zip and uploaded to the nextcloud directory:
/usr/local/nextcloud/updater/
When i click retry it shows the same error. Is the above updater folder the right place to put it?