“Outdated client” / “Outdated server”

One-minute triage: this kick is a version mismatch — your game and the server speak different protocol generations. It has nothing to do with your account, so nothing on this desk’s account lanes will fix it. “Outdated client” means the server runs something newer than you; “outdated server” means you run something newer than it.

The two moves

1. Find the version the server expects (its listing or operator states it).
2. Create a launcher installation for that version and join with it.

The complete answer — which versions interoperate, why, what translation layers change, and how to switch safely without risking your worlds — is the whole job of the version desk:oldercraft.com. This page stays deliberately short so that page can be canonical.