OpenSSH 5.4 has been released today and this is a major upgrade. It will be listed on several mirrors shortly, so it's better to wait for local mirror to catch up with the update.
This version will disable SSH Protocol 1 by default, so if you are still using it (it's a bad decision), you will have to enable it explicitly on your sshd_config configuration file. Another protection is all SSH Protocol 2 private keys will be protected by AES-128 instead of 3DES algorithm. You can get this when updating your passphrase or creating new keys.
Read the full announcement and visit the official website to get it.