(I didn't know where to put this so I put it in general) I installed the beta channel about a month or so ago and I noticed the launcher never changed, and I am unable to download songs this way. I've been downloading them from the songs page. I looked on the forums for a while to see if anyone had brought it up and surprisingly no one had, so I thought I'd ask.
As long as everything else regarding the Beta Channel update works - duets, leaderboards, recognition of the .mlk file extension -, you can just use this one: http://uploaded.net/file/ojp7jccg (http://uploaded.net/file/ojp7jccg)
Also, moving this thread to "Issues and bug reports".
Thank you it works, and yes, everything else worked just fine for the Beta Channel update.