Did you download from caddyserver.com or built from source? If it was the first, I’ve already pushed some fixes that aren’t available for download just yet, but I hope they’ll soon be available. In the meantime, if you really want to try, you can build caddy from source with filemanager plugin.
I am sadly failing to add the plugins when trying to build from source. no action found for directive 'filemanager' with server type 'http' (missing a plugin?)
I ran got get for each plugin and compiled the filemanager with its dependencies.
Looks like i have to wait.
[details=previous_answer]I used the script in the past but after your post, i cloned caddy (master), ran go build into caddy/caddy and copied the binary in my gopath over the binary in /usr/local/bin.
After that, i simply restarted caddy.
Sadly i do not notice any difference. :([/details]
Also a nice weekend to you.
Update
It works after generating from the official curl script again!