Here's what's new with version 5.1.0 (relative to 4.1.3)

Output filtering

The "-f" option lets you perform sophisticated filtering of connections using boolean expressions on just about any field that tcptrace keeps track of

UDP connections

The "-u" flag performs fairly minimal analysis of UDP connections too. Also, hooks were added to the module glue to help.

IPv6

IPv6 is now supported (but not extensively tested yet)

Creating files

the "-O" option will save all packets that pass input filtering (using options "-o -B -E") into a tcpdump/pcap format file