We're chirping for a reason 🤣
I just upgraded all three of my Slackware -current machines. On one I simply used upgradepkg */*.txz, on another the usual slackpkg update && slackpkg upgrade-all. Reboot, a few sanity checks, and back to work. Kernel, glibc, GCC, binutils, XLibre... everything just worked.
That's part of the fun of Slackware: even a big -current update is still boring in the best possible way.
Now let's keep checking those mirrors for 16.0 🥳