Zip-task request returns 'method "POST" not allowed'

I’m attempting to pull down the zip-token for a folder with this command:

curl -s -d “parent_dir=/$LIBRARY/$PROJECT/$FOLDER” -H “Authorization: token $AUTHTOKEN” -H “Accept: application/json; charset=utf-8; indent=4” “$API21URL/repos/$REPO/zip-task/”

(Please accept my apologies for the liberal use of variables…)
I’m following the docs from here : /download.seafile.com/published/web-api/v2.1/files-directories-batch-op.md#user-content-Download%20Multiple%20Items

However - all I receive in return is

{
“detail”: “Method “POST” not allowed.”
}

I can successfully retrieve the Authorisation token for my user, and the repo ID for the library I’m attempting to access, and populate those variables in the command above.

I’m afraid I don’t currently know what version of the server software is in place (I don’t have that access right now), and the api request for server info just returns a ‘requested page couldn’t be found’ HTML page.

Any help would be greatly appreciated.

ARG!
Found the answer - the documentation link in my first post is incorrect.
If you see the link below then it’s obvious
/download.seafile.com/published/web-api/v2.1/directories.md#user-content-Download%20Directory

I hope that this stays visible as a lesson to others such as myself.