Apologies if I'm missing something, but the image name
neon-testing-current.iso now includes a timestamp
like so: neon-testing-20201110-1826.iso.

Also the 'current' link to the download page has disappeared.

How can I get zsync to work ?

Thanks for any help.

No idea why the 'current' directory is missing on the site, the actual url for it gives a 'forbidden' error, which may just mean a permission issue there. It may be resolved later on, unless there was a specific reason to do this.

zsync won't work, if the url to the file is inaccessible.

It broke in the transition to a different server setup for file serving.