I've been trying to develop an app whose functionality is partially to manage events for a user; the app tries to invite other users automatically to the event, when the users are listed, and long story short, I've been trying to use the Graph API to accomplish this as shown here:

https://developers.facebook.com/blog/post/560/

Using versioning, since I get the "event management is not available in version 2.0 or higher" message, I simply add /v1.0/ to the beginning of the URL, which should allow me to make calls using the first version of the API, which was described as the correct way of making versioned calls, according to a Facebook developers page I can't find anymore...

As well, I've been searching Stackoverflow, for example at php - How to invite a users friends to an event? Facebook Graph API - Stack Overflow and Inviting selected users to Facebook-Event (via Graph API) - Stack Overflow, but nothing is working.

I've used the Postman extension as well, to simply try direct POST requests to the facebook Graph API using my access token for the app, in addition to testing out the POST request in the app itself - neither work. It thinks I'm still in version 2.0 even though I specify v1.0 in the beginning of the request URL, like

/v1.0/EVENT_ID/invited?users=USERID1,USERID2,USERID3&access_token=ACCESS_TOKEN

I'm at a loss. This is a big part of the app, need some help if possible, what am I doing wrong? Are there other options? Can I instead invite users to groups, pages, or send them messages? This is baffling me.