Another monthly release for KDE has been released for public few days ago. I was behind schedule because i was out of town. It has been included on Slackware's tree (in -Current only) and it's getting better. In fact, i have just completed downloading it and upgrading my laptop with KDE 4.2.3 along with other changes made in Slackware-Current which now supports for .txz file formats that already uses lzma compression algorithm to compress Slackware packages.
For changes compared to 4.2.2, please see the changelog.