TL;DR: The Flash player embed is going to be deprecated as of August 29, 2016. Developers should move to a supported embed to avoid any problems.
As we march toward a completely HTML5 video player, we want to ensure that our community of developers moves with us. With that in mind, we’re deprecating the Flash player embed as of August 29, 2016. The Flash player may continue to work in the short-term but will be removed at any time without notice. If you run into problems with the embed, there will be no support channels available for it. This deprecation applies to any player not shown in the documentation.
If you use the embeds as shown in the documentation, you’re good to go! No updates needed. Otherwise, please switch over to one of the two embeds shown in the documentation.
player.twitch.tv has supported HTTPS for a long time and video distribution was switched to HTTPS around the time the HTML5 player beta went live for turbo users. There shouldn’t be any issues embedding the new player via HTTPS anymore.