===== MTR 4 for Server Admins =====

Learn what you need to know to migrate your Minecraft server towards MTR 4!

==== Before migrating ====

  * Some addons like [[mtr_addon:nte:start|Nemo Transit Expansion]] and [[https://modrinth.com/mod/transitmanager|TransitManager]] does not have an MTR 4 version. Please double-check your addon list and evaluate your path before upgrading.
  * MTR 4 requires a Minecraft version of either 1.16.5, 1.17.1, 1.18.2, 1.19.2, 1.19.4, 1.20.1 or 1.20.4. Consider upgrading/downgrading your Minecraft version if you are not using a version listed here.
  * **Make a backup before you attempt to migrate, it's an irreversible process!**

==== Migration ====

You may now shut down the Minecraft Server, replace the MTR 3 mod and put MTR 4 mod in the server's mod directory.

After that you can start the server. The first startup may take longer as MTR tries to automatically migrate your MTR 3 data into MTR 4.

After the server has started, you should run the ''/mtr generate'' command to refresh all depot's path and make trains run again.

==== Upgrading Minecraft Version ====

While upgrading Minecraft version may seems like a straight forward steps, there are some attention needed, more importantly:

  * Datapacks may break as command syntax changes between Minecraft version
  * When upgrading from 1.16/1.17 to 1.18+, terrain generation will differs, and you will not be able to regenerate your terrain back to it's 1.17 form, even with the use of WorldEdit.
  * When upgrading to 1.20, the font json format has changed. Continue using the old format would cause (i.e. JCM PIDS) to show up as square font.