First a simple check: "What happens when you simply type in the url to a file including a special character in the address-bar of your browser?"
I think I'm aware of this behavior, agileDownloads (and Oriel) are relatively strict and takes the path "as is". The issue you describe is not that the link in agileDownloads is not working neither a programmatically issue (on joomla or agile Downloads side) - it is the url to the file which is not valid on your hosting/server environment when you are using "non ascii" characters. Please see this article here and here. To work around this limitiations of some servers I've added Prettyfier to my extensions where needed. While using Prettyfier you can write "your own rules" for filenames. This means you can (and should!) place your files with a valid filename (ascii) within a valid path (also only ascii chars) - this will create a valid url for downloading the file(s). And in Prettyfier you simply add your custom rules.
So for example:
original filename: häuser.zip
filename on server haeuser.zip (or so)
Prettyfier Rule: *replace* --> ae --> ä.
So in the filelist you will see the "ä" char and the filename (path to file) is still valid with haeuser.zip.
Background:
Most servers can handle (some sort of) special characters that are not ascii conform - in the worst case the site will crash (white screen of death) if not.
On the other hand, a lot of servers has strict firewall rules which will block url's with special characters for security reasons (see link above). Or simply can't handle the request when using special chars like this.
At least:
Servers can handle such characters individually based on its features / configuration (or do not support it at all) - I've just quick tested it, on all of my webservers, they can all handle requests when using special characters like äöü in the url.
I'm sorry but it looks more like a server restriction / issue then a agileDownloads problem in first sight. You could try to do the following, try to search in google *hoster company special characters in url* if its a large company you would probably find something in the net - on the other hand you can do a simple check (if you have not done it before): "What happens when you simply type in the url to a file including a special character in the address-bar of your browser"?
If i'm right you should either not been able to download the file if its a server limitation (then Prettyfier would be your way to go).
kind regards
Marco
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including a special character in the address-bar of your browser?"
Rate us on JED: https://extensions.joomla.org/profile/profile/details/379934
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