Hold the press! There’s good news on Slackware development front.
Slackware 14.2, the last stable release, saw the light on 30 June 2016. Since then, it has received many security patches but nothing has changed functionally and although 14.2 is super stable, it is also getting stale, in particular its default KDE desktop.
In all that time since the release of Slackware 14.2, the distro has been heavily worked on, and the slackware-current development release is a joy to work with, containing the latest tools and desktop environments.

The frequent and sometimes intrusive updates to -current are keeping the less knowledgeable Slackware users at bay, they prefer 14.2 since that requires minimal maintenance and won’t break after a careless upgrade.
But after almost 5 years of rising anxiety, there is now real movement toward a new stable release.

From the ChangeLog.txt today:

Mon Feb 15 19:23:44 UTC 2021
Here we go again... upgraded to glibc-2.33 and one last mass rebuild for
Slackware 15.0. The only packages upgraded in this batch are glibc and the
kernels - everything else is just a rebuild against the new glibc. Not
rebuilt in this batch: devs (best to just leave this alone), glibc-zoneinfo,
kernel-firmware, rust, linux-faqs, linux-howtos, aspell-en, mozilla-firefox,
mozilla-thunderbird, and seamonkey. There's a new Rust compiler but Firefox
and Thunderbird will need to be patched to use it, so we'll hold off on
those until they're ready for the new Rust either with patches or new
upstream releases. Until we have that and a few more scheduled upgrades I'm
not quite ready to call this beta yet, but you can call it 15.0-alpha1. :-)
Cheers!

I will do my best to update the multilib repository ASAP, I have multilib versions of the rebuilt gcc and upgraded glibc packages ready but occupied with other stuff at the moment.

Have fun upgrading 1550+ packages… again.
Eric