I'm not going to dig back into when Slackware packaged 24.3, but I've not highlighted this fact at all. emacs releases every couple of years. There was nothing to update to until the day before they updated to emacs 24.4.

My general impression is that Slackware keeps up pretty well except when it consciously decides not to. But I haven't been using it very long.

My impression is that upgrades occur only when Patrick J. Volkerding thinks that the extra features or bug fixes are worth his time (testing and checking proper integration with other components included), or for security reasons.

And IIRC upgrades never occur in an already released Slackware just to get extra features.

We also can't forget that Pat is also a human, he might have forgotten to upgrade stuff a few times. Or not get aware that upgrades are avaliable.

But I am just guessing.

I'm forgetting we're still talking about this rolling release nonsense. Yes, it's not a rolling release distro. It's the opposite. The opposite not being old packages but being a large slab of packages that get plonked down all at once without a lot of fussing on your part, kind of like a large city somehow being dropped from space with a great big boom followed by normal city activity. Yes, no wheels, nothing rolling. OP, did someone tell you Slackware was rolling release? Why that expectation?

When I say my impression is it keeps up pretty well I mean emacs, perl, and gcc each were modern enough not to bother me. Perl, IIRC (not at the machine now), was 5.18 in 14.1... very respectable for a year ago. I don't know about PHP, since I don't give a shit about that language. Likewise there's nothing happening in the Linux kernel I care about, so if that's old I wouldn't have noticed. And firefox is a necessary evil, besides which the not so long long term support version forced his hand so it's pretty new now.

So for the OP, if your definition of good distro is rolling release distro, which is kind of the impression I have somehow, then Slackware's not for you. OTH, you may want to find out what Slackware is and why the people who like it like it before moving on.