A major upgrade to OpenSSH is being stabilized: https://bugs.gentoo.org/show_bug.cgi?id=555518
The default of PermitRootLogin for sshd in the new version is "prohibit-password". If you typically log in to the root account over SSH using a password, **IT'S GONNA BREAK**, and you won't be able to fix it remotely unless you have an account that can sudo to root. To maintain the current behavior, set PermitRootLogin to "yes" before you upgrade, and then be careful not to wipe out sshd_config.