On their web site, bouml claims that NetBSD lags behind significantly, having bouml 2.27 packaged.
This is wrong in two ways. Firstly, NetBSD does not have any packages at all, packages for NetBSD are usually created through the OS independent pkgsrc tree, which, while being developed by the NetBSD foundation, is not especially related to NetBSD.
But more than this, having a short look at pkgsrc reveals the following:
$ pwd
/usr/pkgsrc/devel/bouml
$ make show-var VARNAME=PKGNAME
bouml-4.5
$
Evidently, the bouml site is lagging behind significantly? If so, maybe the two sleeping smileys on the site mean just that.