Category:Java Downgrade

This category contains all pages which cover discontinued features that can be obtained by downgrading.

All pages that have this warning will appear on this page and use downgrading:

Warning: Downgrading 

This feature uses downgrading which can result in crashes, data loss, or corruption, and requires specific versions. Follow the page instructions carefully.

Crashing and Corruption

Warning: Game Crash 

This feature can crash the game. Perform at your own risk.

Warning: Corruption 

This feature can corrupt your world. Perform at your own risk.

Downgrading has the potential to cause crash the game or corrupt the world, this is due to the nature of downgrading where the player goes from a newer version to an older version. This may occur because the game is unable to load blocks, items, mobs, etc. This may also cause the worlds files to become corrupted, and depending on the downgrade this may be guaranteed to happen when downgrading.

How to Avoid

If you want to avoid crashes or corruption (usually, some exclusions may apply) follow these general guidelines:

• Always, make at least one backup of the world in case of corruption or continued crashing.
• Remove all items from your inventory that didn't exist in the version you're downgrading to.
• Downgrade while in older chunks, or unimportant chunks if you don't have older chunks (may be necessary that they be old chunks if the world doesn't load).
• Turn the Render Distance all the way down in the settings before loading the world.

If any problems still occur, such as the world not loading it may be due to spawn chunks (spawn chunks are always loaded when reloading). To fix this, do the following:

• Open the "region" folder in the worlds folder.
• Locate the spawn region file.
  • Region files are 32x32 chunks within the world, the spawn chunks are located inside these files and may need calculated if the spawn isn't near X:0, Z:0.
• If the spawn chunks are important, simply move the region files, otherwise these files can be deleted.
  • The usual spawn chunk region files are labeled as: r.0.0.mca, r.0.-1.mca, r.-1.0.mca, r.-1.-1.mca. The .mca will be .mcr for versions prior to 1.1.

If problems persist it's suggested to either create a new world and import the region file/level.dat containing the discontinued feature. Other options include:

• Deleting or moving (for importing later) all region files.
• Deleting or moving (for importing later) level.dat.
  • This will cause worlds to become unloadable so it's suggested to import a fresh level.dat created in the version you're attempting to downgrade to, or creating a new world with the exact same name as the now unloadable world (this tricks the game into loading the world with a fresh level.dat)

Versions to Not Downgrade

The level format has so far changed four times in Java Edition. Performing any of the following downgrades does corrupt your world due to the different formats:

• From Infdev 20100327 and above to Infdev 20100325 and lower.
• From Beta 1.3 and above to Beta 1.2_02 and lower.
• From 12w07a and above to 12w06a and lower.
• From 17w47a and above to 17w46a and lower.