For now, only on browser. However, it will be launched globally on iOS and Android devices on July 3, 2017.
Browser version, released in 2014, has a multiplayer mode. On the other hand, mobile version provides more content and features (except drivable vehicles) such as randomly generated map, better graphics, character skills, etc.
No specific plans for now.
Minidayz supports the following browsers:
Opera v25+, Firefox v32+, Chrome v31+ for Windows
Safari v8.0+, Firefox v32+, Chrome v31+ for MacOS
Opera v12+ , Firefox v32+ for Linux