BackTrack 5 Release 1 will be available on 10th of August,2011. This will complete our first 3 month cycle since the last release. Over 100 bug fixes, numerous package updates and the addition of over 30 new tools and scripts. BackTrack Crew will have a pre-release event at the BlackHat / Defcon Conference a few days earlier. Backtrack 5 R1 (Release one) is available for download on the 10th August, 2011. Back track 5 will complete its first 3 months cycle since its release.
Source: https://thehackernews.com/2011/07/backtrack-5-release-1-will-be-available.html