Data version

A data version, also known as a world version,[1][2] is a positive integer used in a world saved data to denote a specific version, and determines whether the player should be warned about opening that world due to client version incompatibilities.

Upon selecting and loading a singleplayer world, the game checks if the client has a data version newer or older than the selected world. If it does, the game then prompts the user whether they want to back up their world before playing it if the world is older, or warn them that their world may become corrupted if the world is newer.

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. Data versions are necessary because client versions usually cannot be directly compared since they use different formats (i.e., "1.14" and "19w02a" cannot be compared). Data versions may skip many numbers between any release (to leave space for hotfixes), and may be incremented by a non-single amount for a new version.