-- mod.sources, 10/87 -- version 9
Terminal edges and domains (<host> syntax and -D option).
Dead hosts and edges in the input stream.
Empty private list ends scope of privates.
First hop cost in output (-f option).
Penalize deprecated hosts (-a option).

-- mod.sources, 4.3bsd, 1/86 -- version 8
Improved alias treatment.
Routes to domain gateways.
Leading dot in name implies domain.
Link/host tracing (-t option).
Use getopt().

-- mod.sources, 8/85 -- version 7
Private hosts documented.
Homegrown scanner -- it was true what they said about lex.
Makedb.
Domains and gateways.
DEAD back link.

-- net.sources, 1/85 -- version 6
No ! in dbm key.
Network character must be one of !@%: -- dot is dead.
Private hosts.
Discourage hybrid addresses.  
Magic @ <-> % rule.

-- 1983-1984 -- version 5
Reverse sense of the -c (cost) flag.
Use cheapest among duplicate links.
Elide network names in output.

-- epoch (smb version) -- versions 1-4