There seems to be a lot of confusion about 3.1. Not everybody has read Josh's blog so here is a recap:
What can you buy?
Leadwerks normal: C++ and Lua support. (bought via the website)
Leadwerks indie edition: only lua support. (bought via steam)
What is currently released?
Version 3.1 is currently only released for the Leadwerks Indie edition on steam and only for windows.
What has yet to be released?
3.1 Indie edition
Support for Linux and Mac
3,1 Normal edition
Release of 3.1 on Windows, Linux, Mac, Android and iOS Leadwerks 3.1 for Linux and Windows will be released together next, with the exact release date to be determined. Leadwerks 3.1 for Mac will follow this, with mobile add-ons for iOS and Android coming last.