If you check the Flags tab in utorrent you can find lots of alphabets. This what they mean:
D = Currently downloading (interested and not choked)
d = Your client wants to download, but peer doesn't want to send (interested and choked)
U = Currently uploading (interested and not choked)
u = Peer wants your client to upload, but your client doesn't want to (interested and choked)
O = Optimistic unchoke
S = Peer is snubbed
I = Peer is an incoming connection
K = Peer is unchoking your client, but your client is not interested
? = Your client unchoked the peer but the peer is not interested
X = Peer was included in peerlists obtained through Peer Exchange (PEX) or an IPv6 peer told you its IPv4 address.
H = Peer was obtained through DHT.
E = Peer is using Protocol Encryption (all traffic)
e = Peer is using Protocol Encryption (handshake)
P = Peer is using uTorrent uTP
L = Peer is local (discovered through network broadcast, or in reserved local IP ranges)