Do NOT use any beta clients (Or clients older than on this list). Doing so could result in a permanent ban of your account.

Azureus/Vuze

Azureus 2.5.x
Azureus 3.1.x
Azureus/Vuze 4.1.x.x
Azurues/Vuze 4.2.x.x
Azureus/Vuze 4.3.x.x
Azureus/Vuze 4.4.x.x
Azureus/Vuze 4.5.x.x
Azureus/Vuze 4.6.x.x
Azureus/Vuze 4.7.x.x
Azureus/Vuze 4.8.x.x
Misc Clients

btgdaemon 0.9.x
btgdaemon 1.0.x
btpd 0.13
btpd 0.15
btpd 0.16
Deluge 1.2.1 / libtorrent (Rasterbar) 0.14.9
Deluge 1.2.2
Deluge 1.2.3
Deluge 1.3.x
Enhanced CTorrent (dnh3.2)
Enhanced CTorrent (dnh3.3)
KTorrent 2.1.x
KTorrent 2.2.x
KTorrent 3.0.x
KTorrent 3.1.x
KTorrent 3.2.x
KTorrent 3.3.x
KTorrent 4.0.x
KTorrent 4.1.x
KTorrent 4.2.x
KTorrent 4.3.x
leechcraft
leechcraft 0.5.xx
qBittorrent 2.3.x
qBittorrent 2.4.x
qBittorrent 2.5.x
qBittorrent 2.6.x
qBittorrent 2.7.x
qBittorrent 2.8.x
qBittorrent 2.9.x
qBittorrent 3.0.x
rTorrent

rtorrent (libTorrent 0.10.4)
rtorrent (libTorrent 0.11.x)
rtorrent (libTorrent 0.12.x)
rtorrent (libTorrent 0.13.x)
Transmission

Transmission 1.5.4 (For OS X 10.4)
Transmission 1.6.x
Transmission 1.7.x
Transmission 1.8.x
Transmission 1.92
Transmission 1.93
Transmission 2.0.x
Transmission 2.1.x
Transmission 2.2.x
Transmission 2.3.x
Transmission 2.4.x
Transmission 2.5.x
Transmission 2.6x
Transmission 2.7x
µTorrent