Welcome to Geeklog Sunday, May 19 2013 @ 07:26 PM EDT
A quick recap of the new features: Uses PEAR::Mail for emails (so that you can send emails via SMTP), extended content syndication (including a web interface), web interface to rearrange blocks (for admins), supports URL rewriting of story URLs (so that Google can finally pick up the URLs to stories), Static Pages plugin 1.4 and more. Other changes include bugfixes and a much stricter parameter checking for better protection against SQL injection attempts.
This is a recommended upgrade for all Geeklog users. Please note that support for Geeklog 1.3.7 has now officially ceased, so if you're still on 1.3.7, now would be a good time to upgrade.
For those running on the last release candidate (1.3.9rc3): The only code changes were in lib-common.php and admin/user.php, so that you only have to replace those two files (and adjust the version number in config.php).