Data version

A data version is a positive integer used in world save data to denote a specific version.

Usage
Upon selecting and loading a singleplayer world, the game will check if the client has a data version newer than the selected world. If it does, the game will then prompt the user whether they want to back up their world before playing it.

Versioning
Every version of Java Edition since 15w32a, including minor releases and snapshots, has its own data version. The version takes the form of an ever-increasing positive integer, unlike client versions which have different parts of the version separated by periods ( . ). Data versions may skip numbers between major releases, sometimes due to the existence of private test versions in-between.

File structure
The data version is stored in two places inside the level.dat file of a world save: in the root compound named  and also in the  compound named.
 * level.dat
 * : Information about the level.dat file.
 * : An integer displaying the data version.
 * : Versioning information about when the world was last saved.
 * : An integer displaying the data version.

List of data versions
The latest release version,, has a data version of.