If you don't use latest, your ecosystem fragments and risks diamond dependencies. If you do use latest, some of your ecosystem risks randomly breaking.

I think it's best to use latest because the combinatorics of the ecosystem as a whole is much smaller. With everything on latest, you have to play whack-mole on individual services to get them to catch up. But you are doing this just when the community at large is most invested in understanding the process of upgrading.

The alternative is that ancient binary A depends on ancient binary B's legacy behaviour, and B has no need to upgrade but A have a very serious need and now you have a serious problem. Maybe upgrading B breaks C for instance. It's almost uncoordinateable at that point once versions drift significantly. You get true technical debt.