The latest version of utop is 1.17. Please update portage. Changes: 1.16 (2014-10-20) make camlp4 support optional require OCaml 4.01.0 or newer implement wrapper for -safe-string
+*utop-1.18 (29 Jun 2015) + + 29 Jun 2015; Alexis Ballier <aballier@gentoo.org> +utop-1.18.ebuild: + version bump +