The official announcement is not yet ready, but i'm sure that Slackware 13.1 is very close to final release as the RC 1 has been released and it's pretty stable here. I have been following -Current development all this years since i started using Slackware back in 2005 and i don't have any major problems with -Current. Basically, all my needs are fulfilled and i have an outstanding stable system on my desktop, laptop, and also workstation at my office.
As the RC 1 announcement, the base toolchain is now freezed and i believe within few batch of updates, it will soon become a final release and i'm expecting to be released by the end of this month or probably early June
This will be the first Slackware release that includes KDE 4.4.x in history of Slackware's long development