app-emacs/yc is EAPI=3, please update and stabilize since EAPI=3 needs to go away
Feel free to bump this yourself if you understand the documentation and are able to properly test the package. Latest upstream version seems to be 5.2.1, so doing a revbump of 4.0.13 only to update the ebuild's EAPI would be pointless (especially when app-i18n/canna itself is at an even older EAPI).
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=d91658c607b4d4147e5c75c65b7f1baed5dd8776