A couple of differences
 

For some reason I can start LW 4.9.37 Pro and it will connect as a UP. Then shut it down and start FW 4.9.37 it will attempt to connect as UP but can not it Will then switch and connect as a Leaf. If I switch back to LW it will connect as a UP. Both are setup exactly the same but FW shows the firewall Icon until it connects fully then it disappears. LW shows the Icon occasionally but most of the time does not. Also I do not know if you have been playing with the chat feature or not but I actually had a chat yesterday with FW which I have never been successful at before with LW.

Any way I had a little time to play today and thought I would let you know what I have observed, Not that it means anything.

IIRC, the connection code was SLIGHTY modified. but basically you are not needed as an UP. (being a Leaf is actually better than being an UP: less bandwidth used, and better search results) ;)

As far as the chat code goes, no, we have not changed anything with that.

lastly, yes it does mean something... but hopefully it means you will continue to use frostwire :)

Of coerce I will continue to use FW as far as UP goes the only time I download anymore is when I am testing the software. 99% of the time I am sharing 100+GB so for me UP would make more sense. Due to the fact That I have the capabilities to help others connect who do not have the capabilities I have. And yes I know that UL is most likely to get me into trouble in the country that I reside.

being a Leaf and sharing that many files gives better performance to the network ;)