Minecraft Discontinued Features Wiki:Active Bounties

Negative XP Orbs
Negative xp orbs were first theorized in November of 2020 by Bluecrab2 and Bayugoon. During this same conversation, negative xp orbs were proven obtainable through commands, and were thus confirmed to exist. There are multiple potential methods to achieve negative xp orbs. Usefulness for these orbs would be to create negative durability equipment of any variety, as negative xp orbs that are absorbed while holding mending items decreases the durability instead of increasing.


 * It was initially theorized that negative xp values on the player could be reached by jumping in Beta 1.9 Pre-release 2, however this was disproved as it hit a hard block at half the 32 bit integer limit


 * The XP command is usable in survival in 17w45a. Using this command you can assign a negative value, however it only effects the player's Score level, it does not modify the XpLevel.


 * XP orbs merge to combine xp values, however there is a limit disallowing them from ever reaching a negative value. Code has been tested in 1.12, and the game analyzed in 1.17 , with repeat behavior in both cases.


 * Xp can be mass duplicated in Beta 1.8 Pre-release 2, allowing for the player to reach a negative value. This can be done by dying with xp while on a server, which doubles the dropped experience each time. A player could potentially die with a negative xp value in a future version and then drop negative xp orbs. All tested versions are in the table below.


 * Smelting 2,147,483,647+ items from a specific furnace recipe sets the respective RecipeUsed value within the furnace negative in certain versions, however this was later proved to overflow to 0 in certain specific versions. Technically speaking, considering this value is multiplied by the xp for a given recipe, when mining the furnace, the xp dropped from it should be negative. However, through extensive testing, mining a furnace with negative recipes used always drops 0 xp (tested in versions listed below). Many differing methods of breaking have been tested, all with the same outcome. Potentially taking an item from the furnace output slot would have a different outcome. Furnaces only store experience from 18w09a onwards, meaning these should be the versions to search through. Code analysis of furnace xp storage has yet to be completed to properly debunk this method. Note even if this method is proven to work, which current research has proved unlikely, it would still be infeasible since it requires over 2 billion items to be smelted.


 * Code analysis of many versions from the introduction of XP (in the Beta 1.8 prereleases) to the present day show that any source of XP orbs being created will have a value between 1 and 2477, as a result of the code that splits XP drops into separately sized orbs. If any method of negative XP orbs is to be found, something must be found (likely in a snapshot or other development version) that does not use the splitting code. If such a method exists, then it can be used to create a negative XP orb by obtaining a value higher than 2477, such that  (32768-65565 is the first valid range). The value variable is cast from an integer to a short when writing to NBT, allowing the value to overflow such that it becomes negative if the value is in a valid range.



One Item Villager Trades
There is a report of a 12w21a server crashing and then converting all villager trades to 1 item for 1 item. This would allow for several varieties of discontinued trade amounts were it to be proven.


 * The server was not confirmed to be entirely vanilla, and the reporter did not have access to a world download or crash logs for verification.


 * Crashing a singleplayer world in 12w21a has had varying results, however so far it has not replicated the described behavior. Crashing a world while loading a villager has resulted in the villager's region not loading in correctly and has also had a separate occurrence of nothing happening during the crash. The villagers would also reset trades, however they would reset within the normal trade ranges.

