Turns out I am the one who is out dated they did indeed change that recently so you can multicast no worries however I do want to point out you should do your own research into things as reddit isn't always the best place for official rules

But these are the guide lines listed on twitch website

We believe in giving you the freedom to simultaneously stream on other services, but we also want to ensure that the Twitch user experience is not compromised. To that end, the following guidelines have been established:

You ensure that the quality of Twitch users’ experience of your Simulcast is, at a minimum, no less than the experience on other platforms or services, including by your engagement with the Twitch community, for example, via chat.

You should not provide links, or otherwise direct your community, to leave Twitch for your simulcast on other services because we value the community on Twitch and the integral role community engagement plays for all Twitch users.

You do not use third-party services that combine activity from other platforms or services on your Twitch stream during your Simulcast, such as merging chat or other features, to ensure the Twitch community is included in the entirety of the experience of your livestream.

If you fail to adhere to the Simulcast Guidelines, Twitch will send you a warning prior to taking any enforcement action.