Not sure about anything official on that half, but, from what I read there are a couple approaches, most just not ideal or not yet widely compatible/supported.
A lot of multiplayer services are being offered through the various web stores (play, amazon) but you will have to work with their sdks, this just limits them to their platform.
From within construct 2 there is the option for PHP/MySql usage, that should work on all platforms having network connectivity.
I did a multplayer tutorial for php and mysql recently. Based on a game I made TankWars .
Updates happen every second or so.
Not high performance.
Not ideal for real time play (tankwars drives slow hehe)
But Turn based methods should work great.
Should work on all platforms supporting the Ajax object.