One security update was released on today's update, which is PHP 5.3.6. It was released by PHP team yesterday, but it has been included in Slackware-Current since it incorporates so many bug fixes. Please note that PHP 5.2.x is no longger supported by PHP, so please start upgrading to PHP 5.3.x series.
The kernel packages are being rebuilt to add Firewire and FireDTV modules since IEEE1394 firewire stack is no longer exists in 2.6.37. Several apps are being upgraded such as usbutil, cmake, libraw, packages from XOrg (libX11, xf86-*, xorg-servers), and gnuplot.
One interesting news is that Firefox 4.0 RC1 is now included in the main tree replacing the old 3.6.x series. Since Mozilla announced that RC1 will become a final version if there are no major blocker, Pat decided to include it as the default application in a new installation of Slackware 13.37. If you still prefer to use 3.6.16, you can still use it and it will be maintained under 13.1/patches as long as the upstream still supports it.
Those who like to compile the new Linux Kernel 2.6.38 can test the new .config files that are now provided under /testing/source/linux-2.6.38-configs.
If my predictions are correct, Slackware 13.37 should be released by the end of this week or at most next week. It's just a wild speculation based on the Changelog. The final date of the released will only be known by Pat himself.