ipv4/ipv6 selection strategy?

[Hakkk]

The scheme is like below:

uTorrent supports both ipv4 and ipv6;

My network supports both too;

And a tracker also responds to peers with both protocols.

Then what is the strategy that uTorrent works out to contact the tracker and to connect other peers?

ipv4 or ipv6 only, or use both alternately, or randomly?

Thanks.

[Switeck]

uTorrent "prefers" IPv4, but accepts IPv6.

[Hakkk]

Thanks for the reply.

In practice, do trackers also affect the preference of protocol selection?

Here we (~4000 users) have both IPv4 and IPv6 connections to a PT tracker, but in the profile page of the PT site most of the users are labeled as IPv6 users, and in the peers panel of uTorrent there are also a lot of IPv6 addresses and few IPv4 addresses. Is this normal or abnormal?