Latest stable smokeping in portage is 2.3.5, latest upstream 2.3.x is 2.3.6 from 04/2008. Please bump ebuild in portage.
Same reasoning as https://bugs.gentoo.org/show_bug.cgi?id=325297#c1 BTW, from the top of my head this packages need to update dependencies and probably they collide with some packages (just check recent bugs in ChangeLog if you are interested in this job). Also note that bump is a short goal. In future, somebody will have to maintain old packages and since I don't have time for this probably you could to step in and work on bugs.