TBB 2.3.20-alpha-1-* is unsafe, but still recommended
TBB 2.3.20-alpha-1-* is now known to be unsafe (it contains Firefox 14.0.1), but it is still listed in recommended-versions. Please make sure that someone unrecommends it sometime this decade.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information