Just upgraded to 20501, and I have problems with uTP uploads, their speed is practically zero (16-32kB / min / connection). Never seen this problem before, it also worked well for me with build 20367. It seems that fallback to the old uTP method (bt.trans_disposition = 15) solves the problem, I get normal upload speeds that way. The problem is only with uTP uploads, uTP downloads are the same fast as usual. Example : http://i28.tinypic.com/i6xqbp.gif XP x86, cable connection, behind a NAT router.