This is a data schema upgrade, and I'm planning to remove the backwards compatibility in about a month from now.
The logic to upgrade these records has been in place for a few weeks already; if you have made a logged in post/comment/chat in 2019 you should be good.
Worst case, if you have an account that doesn't get upgraded this way; it will continue to work; and your previous posts/comments will still be on nab; but they will not be visible on your profile when I flip the switch. Content created afterwards will be present on your profile regardless of whether you upgrade beforehand or not.
So please, log in and say hi when you get a chance. But if you don't it's probably not that big a deal either.
Edit for clarity: Either a post, comment or chat message while logged in will trigger the upgrade, you don't have to do one of each.