Its the latest version. I installed it from scratch yesterday just to make sure I wasn't doing something wrong with replacing the font awesome files. It's just a local test site to try and get the feel of T3 and joomla. Framework 2.4.0 Template t3_bs3_blank 2.1.6. Honestly I don't know if it was working before I replaced the css files or not because I was depending on the MegaMenu preview. I will install from scratch again and let you know if it works on the frontend and isn't showing up on the backend.
Just out of curiouosity, I checked the packages for both the plg_system_t3.v2.4.0 and the t3_bs3_blank.v2.1.6 and the font-awesome.css has this as the first line
/*!
* Font Awesome 4.1.0 by @davegandy -
http://fontawesome.io - @fontawesome
* License -
http://fontawesome.io/license (Font: SIL OFL 1.1, CSS: MIT License)
*/
/*
I don't know if the complete package has these files updated or not as I installed them seperately but it appears that they are both still using the older version of font-awesome.