So upgrade to 1.25? What reason could you possibly have to be so far behind?

I can understand staying one version behind latest, to not be exposed to brand new bugs, which do happen, but staying two versions behind is pointless.

Using a release less than two months is hardly “so far behind”. The 1.24 series had considerable regressions that have taken a number of patch releases to fix, it stands to reason that the same would be true of newer releases. Given there's still miscompilations getting fixed as late as 1.25.8, and 1.25 brought in large changesets for the new experimental GC, sticking it out while 1.24 is still getting patches a mere handful of weeks ago is not unreasonable.