A version change didn't apply, reverted, or won't load after restart — what's wrong?

If a version change didn't take, reverted on its own, or won't boot after a restart, the culprit is usually one of three things: the startup file still points at the old jar, an incompatible add-on is blocking boot, or the server just needs a full restart. Here's how to track it down.

Common causes

A missed restart, a startup variable (on the Settings page) pointing at the wrong jar, an incompatible plugin or mod, or an admin-locked Docker image can all make a version change appear to fail or roll back.

Diagnosing the problem

1. Confirm the install finished on the Software page, then fully restart the server from the Console tab.
2. Check the startup variables on the Settings page point at the newly installed jar/file.
3. Read the Console for a plugin or mod that's incompatible with the new version, and remove or update it.
4. If it keeps reverting, an admin-locked Docker image or a manual jar on the Settings page may be overriding the change — check Settings, or open a ticket.

Tip: The console's first error after a failed version change names the incompatible add-on nine times out of ten.

Frequently asked questions

It's stuck on the old version — why? Verify the jar variable on the Settings page matches the new install.

It won't boot on the new version — what do I do? Remove mismatched plugins or mods, then retry.