Minecraft 25w03a

25w03a is the second 1.21.5 snapshot, released on January 15, 2025, and its biggest addition is something most survival players will never touch. Mojang moved its GameTest framework into the regular game. A test is a saved structure plus a definition of how to run it, and the new /test command can create, run, locate, reset and stop tests. The framework expects tests to run in a separate superflat world.

Two technical blocks came with it, the test block and the test instance block, and you can only get them through commands or the Operator Items tab. A test instance block stands for one test placed in the world and is how you control it. A block-based test needs at least one test block set to start and one set to accept. If you publish redstone builds or data packs, this gives you a way to check that they still work after an update without walking through them by hand.

Saddles got a round of fixes. On a camel, horse, donkey or mule, the saddle now stays visible when the animal has Invisibility, and it no longer turns red when the animal takes damage. Enchanted saddles show their glint on the mob, and Thorns and Curse of Binding work on a saddled mob. A saddle dropped by a pig or strider keeps properties like its custom name. The horse.saddle item slot was renamed to saddle and works for every mob that can wear one.

Leaf litter can now go in a composter. When an End portal or exit portal changes state, blocks in its area drop as items instead of being overwritten. Data packs moved to pack format 63, and 39 bugs were fixed.