MM Heroes: Era of Chaos were released worldwide! If you preregistered I can only guess that you will receive your "pirate Catherine skin and legendary pack" when connecting the game with your Ubisoft profile. Which needs to be the same like your pre-registration e-mail.
Let us know, if you play the game ;)
MM: Elemental Guardian - a few days ago received series of updates. Improving graphics, stability and running on phones with 1GB of RAM.
The Last one bring new monsters and spell, being called: "Dark and Light Update". In April Dev Sergi released roadmap, you can check it here. Some of its planned futures were however already delayed, like "Infinite Turns Strategy". As there would be too much changes at once.