Tutorials/Downgrading

Downgrading is an action of loading a world in the older version/snapshot than the version/snapshot of that world last loaded. Downgrading is dangerous, it can cause the world to corruption, data loss or even worse, crash.

Downgrading screen
When you in the singleplayer menu, if the world last loaded in the newer version/snapshot than the current version/snapshot, the version name in the world data of that world will have a red color. When move the mouse to that world, an exclamation mark pops up at the left of the play button. When move the mouse to that exclamation mark or the play button, that exclamation mark will turn red and a red text will pop up and say: "World was saved in a newer version, loading this world could cause problems!". If you right-click on that exclamation mark or that play button; or select that world then right-click on the button "Play Selected World", a screen will pop up with the text that say: "Downgrading a world is not supported This world was last played in version ; you are on version . Downgrading a world could cause corruption — we cannot guarantee that it will load or work. If you still want to continue, please make a backup!" The screen also have three buttons that name in order: "Create Backup and Load", "I know what i'm doing!", and "Cancel". The use of the buttons is shown in the table below.

When you downgrading a world, that version/snapshot world last loaded will update to the current version/snapshot.

Consequence
The consequence of downgrading a world is:
 * Any loaded chunks in that world will update to the new chunks.
 * Any blocks, items, entities, enchantment, effects, particles, sounds, biomes, advancement, etc. that don't exist in that version/snapshot will be remove from the world.
 * Downgrading a world can cause the world to corruption, data loss and crash.