R3 focuses on bug-fix as well as the addition of over 60 new tools. A whole new tool category was populated “Physical Exploitation”, which now includes tools such as the Arduino IDE and libraries. Backtrack Team have released a single VMware Image (Gnome, 32 bit), for those requiring other VM flavors of BackTrack. BackTrack Team have also released a one VMware Image for those needing a 32-bit version of the BackTrack software. Back track 5 R3 has been released.
Source: https://thehackernews.com/2012/08/backtrack-5-r3-released-download-now.html