The new version has been released. However There is no clear changelog list.
*** Bug 585272 has been marked as a duplicate of this bug. ***
commit e2c2978ad080e6c44532551b2e9299e796bdbae9 Author: Lars Wendler <polynomial-c@gentoo.org> Date: Thu Sep 22 12:52:41 2016 sys-auth/pam_yubico: Bump to version 2.23 (bug #585272). Package-Manager: portage-2.3.1 Signed-off-by: Lars Wendler <polynomial-c@gentoo.org>