Mac client status

Hi. I am just one of those guys who plays LOL on a Macbook Pro.

I've been seeing the word "beta" on the bottom of my LOL screen for quite a while.

Today, I got El Capitan, and I know I got a little thing called Metal underneath it somewhere.

So, my question to Riot is, where are we with the Mac client and when will we be using that weird Metal thing? (You know, it's not just Mac players who are worried, Morde is confused and lost. I think he doesn't feel very well.)