Why can’t you change the headers? It’s a fairly standard thing for a application making a HTTP request to be able to set headers.
There have been numerous emails.
Numerous updates to the developer documentation and updates pushed out via the Developer Weeky Twitch stream and this very forum
The last post of which covers the “shutdown” testing timeline
You should move off Air, to something that does let you set custom headers making requests, last time I was in flash (years and years ago) you could make requests with custom headers. (I actually thought air was dead but turns out it had a release recently)
This section clearly states the requirement to be able to set the Accept header.
Note that default version of the API will not be updated to v5 after the v3 shutdown and therefore the Accept header will be required for any request to the kraken namespace.
This section above, you decided to omit from your initial screenshot of the docs, or you seem to have a very outdated screenshot.
Whilst the undocumented solution of api_version=5 currently works this does not guarantee it will continue to work.
Generally speaking, most APIs expect the ability for you to set custom headers.
Probably the easiest solution for you is for your Air Application to make a request to your backend server, and then your server can fetch and maintain a cache of who is live on the stream and deal with all the fun of the actual request headers and all. You probably already have such a server in order to serve updates for your app.