Does µTorrent support Protocol Encryption (PE)?
Yes, as of version 1.4.1 beta build 407. It is compatible with Azureus and BitComet 0.63.
Protocol Encryption (PE) is a joint specification between Azureus and µTorrent. It is designed to bypass throttling and/or blocking of BitTorrent traffic by an ISP.
You can choose Protocol Encryption’s mode of operation in BitTorrent. Here is an explanation of the various options you can choose from:
• Disabled: Does not encrypt outgoing connections, but will accept encrypted incoming connections.
• Enabled: Attempts to encrypt outgoing connections, but will fall back to an unencrypted mode if the connection fails.
• Force: Attempts to encrypt outgoing connections, and will NOT fall back to an unencrypted mode if the connection fails.
• Allow legacy incoming connections enables or disables incoming legacy (non-encrypted) connections.
All modes will accept incoming encrypted connections (and the encryption is 2-way)!
It is NOT recommended to turn off "Allow legacy incoming connections", unless you cannot have any non-encrypted connections (typically in conjunction with Forced), in which case turning off "Allow legacy incoming connections" is acceptable.

Does µTorrent support DHT or Peer Exchange?
As of version 1.2, µTorrent supports DHT, and as of version 1.4.1 beta 407, supports Peer Exchange (only compatible with µTorrent peers at the moment). It respects only the private flag included in the .torrent. The private flag will disable both PEX and DHT.
µTorrent will NEVER support private flags given by the tracker in the announce response! It is a dirty fix, and is EXTREMELY unreliable. Only the private flag embedded into the torrent will be supported because it is reliable and relatively secure by design.

See What is DHT? if you don’t know what DHT is.

Does µTorrent have a plugin system?
No, it does not. This feature will not be added, please do not request it.

Does µTorrent support UNC-style paths (e.g. \\\C$\ ) / network drives?
Yes, as of 1.3.1 beta build 374. However, fragmentation may be higher when saving to a network drive, since allocating space across the network is not possible.

Does µTorrent have Unicode support?
Yes, it does, as of µTorrent 1.2.3 beta 356. The same executable can be used for 9x/ME systems, but Unicode itself will only work on NT3.51 and later (2000/XP/2003 are NT).

Does µTorrent support multi-tracker torrents?
Yes. µTorrent currently announces to all tracker groups at the same time, but only one tracker per torrent group. To see the trackers in the torrent, simply double click on it, or right click and select Properties. Trackers separated by an empty line indicate they are in separate tracker groups. (Multitracker Details on Depthstrike)

Does µTorrent support UPnP (Universal Plug’n’Play)?
Yes. As of 1.5.1 beta build 462, UPnP works on ALL OSes. You can turn it on in Connection. If it works properly, then you should see the port has been mapped in the Logger tab, and once you receive an incoming connection. You can use the port checker in the Speed Guide (Ctrl G) to see if it really is working properly. If it never turns green after running torrents for a while, or says Unable to mape UPnP port, it most likely means that something went wrong, usually a software firewall blocking incoming connections. See this question for more info about the UPnP error. If all else fails, the port may still have to be forwarded manually. See How do I forward ports? for an explanation of what UPnP is for and other info related to forwarding ports.

Does µTorrent support RSS feeds?
Yes, as of 1.3.1 beta build 374. Be warned that users of version 1.4 will have to remake their filters when upgrading to 1.4.1 beta 405 or later. Click here to see a detailed tutorial for RSS.
Thanks to TVTAD for the use of their icons!

Does µTorrent support Super Seeding mode?
Yes, it does. Double click on the torrent and check the Initial Seeding box to turn it on. For an explanation of what Super Seeding is, read this page
Please note that Super Seeding should ONLY be used if you are the -ONLY- seeder in the swarm, with no exceptions. It is also only effective with at least 2 peers in the swarm, and should generally not be used when you have high upload speeds.

Does µTorrent support endgame mode?
Yes, it automatically goes into this mode when the pieces remaining are all being actively downloaded. This mode helps make getting the last pieces of the file take much less time than normal.

Does µTorrent allow selective file downloading?
Yes, left click on the torrent, then click on the Files tab. Select the file(s) you want to change the priority of and set them to "Don’t Download." You may have to press F5 to make the Detailed Info section, which has the tabs, show up. You can also do this when you load the torrent in the BitComet-style Add Torrent dialog. However, this dialog will not show up if you have "Put new downloads in:" turned on by default. You can turn on "Always show dialog on manual add" in the Downloads section or use File -> Add Torrent (no default save).
Pre-allocate no longer allocates all the files when skipping, only the files you choose.

Does µTorrent support Manual Announce?
Yes, right click on the torrent and select "Update Tracker". It is the same function under a different name.

Does µTorrent support HTTPS (SSL) or UDP trackers?
µTorrent 1.6 supports SSL (for trackers and RSS), but not UDP trackers. UDP tracker support is not likely, due to many flaws with the UDP tracker spec.

Does µTorrent support trackerless torrents?
Yes, it does. The torrent creator can also make trackerless torrents. You cannot use Magnet URIs to download a torrent, though the function is planned for the future.

Does µTorrent have an embedded tracker?
Yes, it does. You can turn it on by enabling bt.enable_tracker in the Advanced section. However, it is a very simple tracker, with no web interface, or even the ability to see what torrents are hosted on it. It is not designed for anything requiring security or large-scale. A stand-alone tracker is much better for this. It allows all torrents, external or not, to be tracked on it when enabled.
Once you have enabled it, you can use it by simply putting the tracker’s URL into a torrent. The tracker URL is http://your.ip:port/announce (port being µTorrent’s incoming port). IP can be external or internal, depending on if you want to use it in a LAN or across the Internet.

Does µTorrent support multi-scrape?
Yes, as of 1.3.1 beta build 374. It automatically detects trackers that do not support multi-scrape and falls back to single scrape mode for that tracker.

Does µTorrent have a boss key?
Yes, it does as of 1.3.1 beta build 374. The boss key is a function that hides and unhides the client window and the system tray icon when you press the hotkey.
You can set the key by going to Other, clicking on the box under Boss Key, and pressing the keys you want to use. Letters and numbers cannot be used without Alt, Ctrl, or Shift (µTorrent appends Alt if pressing a letter or number alone). F keys can be used alone. Whatever key you set here is global and overrides other programs’ hotkeys. To clear the boss key, click on the box and press either Delete or Backspace.

Does µTorrent automatically ban peers after a certain number of hashfails?
Yes, it does, after 5 hashfails. It will ban and kick the peer for the entire session. To reset the bans on the torrent, right click the torrent, Advanced -> Reset Bans.

Does µTorrent have a BitComet style add torrent dialog?
Yes, it does. It’s on by default. If you use "Put new downloads in:", you must either turn on "Always show dialog on manual add" or use File -> Add Torrent (no default save). In this dialog you can edit the torrent properties (click Advanced), choose files (right click for Select or Deselect all), pick a label, choose the save folder (and rename it), skip the hash check, and have the torrent get added in stopped mode.

Does µTorrent have a web interface?
Yes, it does. See this page for further details.
Can you make µTorrent automatically run a program after the download finishes?
Yes, in the torrent properties (right click -> Properties, or the Advanced button in the BitComet-style add torrent dialog), click on the Advanced tab. You must do this on a per-torrent basis.

Is there any foreign language support for µTorrent?
Yes, you can get the language file from µTorrent’s download page. Simply drop utorrent.lng into %AppData%\uTorrent and restart µTorrent. µTorrent should automatically change to your system language once you restart it. If it doesn’t, open the Options, go to General and select your language from the drop down list.