Hi!
We've got a new dev release: Tor 0.4.0.1-alpha. It's in feature-freeze, and it needs testing. The code is now available at https://dist.torproject.org/ -- I'll send out the official announcements once the download page has updated.
You can read the changelog online at https://gitweb.torproject.org/tor.git/tree/ChangeLog?h=tor-0.4.0.1-alpha
A note: for the new padding backend, we now include some code that implements different statistical distributions. That code needs stochastic tests -- and stochastic tests have a false positive rate. This means that right now, the "test-slow" test suite will fail about 1 time in 300 with a message saying that some stochastic test has failed. I realize that this is inconvenient, especially if you're running a bunch of builds: We're going to try to lower the observed false positive rate for these tests between now and 0.4.0.2-alpha.
happy hacking,