An update should not cost you your world.

Read the release notes before installing

A modpack update can change content, recipes, configuration, or the loader. Check the publisher’s release notes and migration instructions for the exact versions you are moving between. Not every update is safe for every world.

Have every player prepare the same destination pack version. Keep the old client instance until the new server has been verified.

Make a complete, consistent backup

Tell the group when maintenance starts. Stop the server and confirm the process has exited. Back up the whole directory, not only a folder you assume is the world. Modded state may include teams, claims, player data, and configuration outside the obvious save directory.

Keep a copy on a different machine or in object storage. Record the source pack version next to the archive. Verify its checksum and test extraction.

Stage the new release separately

Use a new directory with the official server distribution. Follow the ATM team’s current instructions for carrying across world data and custom configuration. Blindly overlaying old mods onto new ones can leave duplicate or incompatible files.

Start a copy of the world on an isolated port. Check the console, sign in, visit important bases and dimensions, and verify inventories and team progress. A green process indicator alone does not validate the world.

Keep a real rollback boundary

Before reopening the server, agree on a short validation window. If validation fails, stop the new server and restore the complete pre-update copy with its matching pack version. Do not downgrade a world that has already been modified and assume it is safe.

Progress made after the backup may be lost when rolling back. Explain that to the group before maintenance, and retain the failed state for investigation.

How the GolemHost pilot handles this

The pilot keeps pack versions pinned. Self-service modpack upgrades are not currently offered. The backup and restore controls protect supported configuration changes; they do not guarantee compatibility between arbitrary pack versions.