I'm running amavisd/spamassassin with the updated IO::Socket::IP with no problems.
Here are all the hits from a search of .pm and .pl files from ports source unpacked at the end of August - (require|use).*IO::Socket::IP. We could add deps to these pretty easily. p5-ldap-0.65/perl-ldap-0.65/lib/Net/LDAP.pm 35: eval { require IO::Socket::IP; IO::Socket::IP->VERSION(0.20); } amavisd-new-2.10.1/amavisd-new-2.10.1/TinyRedis.pm 22: if (eval { require IO::Socket::IP }) { amavisd-new-2.10.1/amavisd-new-2.10.1/p0f-analyzer.pl 72: if (eval { require IO::Socket::IP }) { p5-Mail-SpamAssassin-3.4.1/Mail-SpamAssassin-3.4.1/lib/Mail/SpamAssassin/Plugin/DCC.pm 96: if (eval { require IO::Socket::IP }) { p5-Mail-SpamAssassin-3.4.1/Mail-SpamAssassin-3.4.1/lib/Mail/SpamAssassin/Util/TinyRedis.pm 31: if (eval { require IO::Socket::IP }) { p5-Mail-SpamAssassin-3.4.1/Mail-SpamAssassin-3.4.1/lib/Mail/SpamAssassin/Client.pm 65: if (eval { require IO::Socket::IP }) { p5-Mail-SpamAssassin-3.4.1/Mail-SpamAssassin-3.4.1/lib/Mail/SpamAssassin/DnsResolver.pm 58: if (eval { require IO::Socket::IP }) { p5-Net-HTTP-6.09/Net-HTTP-6.09/lib/Net/HTTP.pm 11: if (eval { require IO::Socket::IP }) { p5-Net-INET6Glue-0.603/Net-INET6Glue-0.603/lib/Net/INET6Glue/INET_is_INET6.pm 14:if ( eval "require IO::Socket::IP" p5-IO-Socket-SSL-2.016/IO-Socket-SSL-2.016/lib/IO/Socket/SSL.pm 288: require IO::Socket::IP; p5-Mojolicious-6.17/Mojolicious-6.17/lib/Mojo/IOLoop/Client.pm 5:use IO::Socket::IP; p5-Mojolicious-6.17/Mojolicious-6.17/lib/Mojo/IOLoop/Server.pm 7:use IO::Socket::IP; p5-Plack-1.0033/Plack-1.0033/lib/HTTP/Server/PSGI.pm 72: eval { require IO::Socket::IP; 1 } 73: or Carp::croak("