Mechanic Rollback brings back Java Edition mechanics that recent updates changed or removed. Each feature can be switched off on its own. There are no dependencies, and Fabric API is not needed. The mod is server-side: drop it into your server's mods folder and players can join without installing anything.
What it restores
| Feature | Removed / changed in | Config key |
|---|---|---|
Spawn chunks: the chunks around world spawn stay loaded and keep ticking with nobody nearby, like before. The radius works like the old spawnChunkRadius game rule (default 2). |
1.21.9 | spawnChunks, spawnChunkRadius |
| Old Mining Fatigue: Mining Fatigue III (Elder Guardians) is back to its old strength. It was 10x weaker in 26.3. | 26.3 | legacyMiningFatigue |
| Shield knockback: a hit that is fully blocked by a shield knocks the blocker back again. | 26.3 | shieldKnockback |
| Endermen in boats/minecarts dodge projectiles again, so enderman holding cells and farms keep working. | 26.3 | endermanProjectileImmunity |
Configuration
config/vanillarestore.json is created on first start. Set any option to false to get the current vanilla behaviour. Restart the server after editing.
{
"spawnChunks": true,
"spawnChunkRadius": 2,
"legacyMiningFatigue": true,
"shieldKnockback": true,
"endermanProjectileImmunity": true
}
Notes
- Mining speed is also predicted by the client. If only the server has the mod, players mining under Mining Fatigue III may see blocks break and then reappear. Install the mod on the client as well for smooth mining.
- Works in singleplayer too (install it on the client).
- Attribute swapping and the MC-101770 projectile redirection are still in vanilla 26.3, so this version does not change them. If Mojang removes them, a future update will bring them back.
Compatibility
Minecraft 26.3, Fabric Loader 0.19.5+, Java 25.

