If you have old acquaintances you haven't talked to in a long time, feel free to reach out to catch up. Even former classmates you might not have done much with, over time, can be considered distant friends.
I've been recently messaging a few classmates I haven't talked to in a decade, and we've been able to have fantastic conversations. We've also arranged to talk more regularly.
Someone has to make the first move, so why can't that person be you?