A New Generation: One Year On from the End of Slimefun

Hi Everyone,

Just over a year ago, on 11 October 2025, TheBusyBiscuit and the Slimefun team announced the end of Slimefun's active development.

After 12½ years, the plugin that gave us jetpacks, magic, cargo networks, electricity and countless hours puzzling over the Ancient Altar was being laid to rest. The repository would be archived, and the last experimental build for Minecraft 1.21 would be the last one ever released.

It was a goodbye written with real warmth, and it deserved one. Slimefun began in 2013 as a first Java project with a handful of items. Over the years it grew into something thousands of servers and hundreds of addon developers built their worlds around. As the team put it, "the most important focus has always been fun."

We've never forgotten that.

The announcement left one door open: anyone who wanted to carry Slimefun's legacy forward was welcome to try.

So we took it on.

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Taking It On

Picking up a project with more than a decade of history is no small thing. Keeping Slimefun alive, let alone moving it forward, meant going far deeper than an update for the newest Minecraft version. It meant opening up every system, understanding why it worked the way it did, and rebuilding what needed rebuilding.

And that was just Slimefun itself. Behind it stood an army of addons, each one needing to be updated, fixed and brought along with it.

It was a monumental task.

Over the past year we have:

• Brought Slimefun in-house and made it our own, kept current with modern Minecraft and Paper.
• Rewritten thousands of lines of code, untangling systems that had grown piece by piece over twelve years.
• Patched thousands more bugs: old ones, new ones, and ones nobody knew were there until they bit someone.
• Overhauled storage and BlockStorage from the ground up, so it's faster and sturdier and capable of things the old system never could manage.
• Updated the whole army of classic addons, maintaining and fixing the ones you know and love so none of them were left behind.
• Built brand-new addons of our own.

We've done things with Slimefun that were never possible before.

More Importantly, We Listened

None of that code matters if it isn't what you want to play.

Every bug report, every suggestion, every "wouldn't it be cool if…" and every frustrated message about a machine that wouldn't behave has shaped this year's work. Many fixes and features began as a chat message from a player, and many still do.

Slimefun has always been a community project at heart. You told us what was broken, what was missing and what you dreamed of building, and we listened.

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But That Isn't Enough, Is It?

Today we're proud to announce three brand-new addons, now in development and testing. We're aiming to bring them to the server by the end of the year.

⚙️ Hydraulics: Steam, Pipes and Copper

Power your base the old-fashioned way.

• Steam power. Boil water in Solid Fuel, Lava and Lightning Boilers, or tap a running reactor with a Heat Exchanger. Pipe the steam into turbines to power your Slimefun machines.
• Pipes and pressure. Copper, Brass and Rift Pipes carry water, lava, steam, oil, fuel, lubricant, coolant and molten metal. Keep an eye on your Pressure Gauge: push a pipe past its rating for too long and it will burst.
• Living copper. Copper pipes and tanks weather over time and lose strength. Wax them to keep them pristine, or scrape them back with an axe.
• Steam machines. Steam Hammers, Presses, Mills and Smelters. A Distillation Column that turns crude oil into fuel, lubricant, tar and plastic. A Crucible and Casting Basin for molten metal.
• Moving structures. Steam Rams that slide whole walls, lift portcullises and raise floor hatches. Drawbridge Winches, Steam Lifts, Rotating Platforms, a Steam Excavator and a Gantry Crane.
• Steam gear and clockwork. Pneumatic tools, Piston Boots and Brass Goggles, plus Clockwork Keys that put copper golems to work.

🛡️ Sentinel: Security for Your Base

Your base, your rules.

• Access control. Door Locks, Keypads, Keycard Readers with security levels and visitor passes, and Biometric Scanners that know who belongs.
• Surveillance. Presence Sensors, Doorway Scanners, Tripwire Lasers and Motion Cameras you can watch live from a Monitor Console.
• Traps and bait. Decoy Ores, Decoy Chests and Tamper Seals that tell you exactly who went where they shouldn't.
• Response. Alarms that can message you on Discord while you're offline, Panic Buttons, Searchlights, and a Lockdown Controller that seals every door and shuts down your machines.
• Deterrents. Repulsor Pads, Disorientation Emitters and Stun Turrets for unwelcome guests, only where PvP rules allow.
• A full event log of every trigger, entry and denial.

⚗️ Alembic: Experimental Alchemy

Brewing, but nothing like vanilla.

• Aspects. Every ingredient carries hidden aspects: life and rot, ember and frost, light and shadow, void and aether. The two strongest in your mix decide what you brew.
• A balancing act. Opposed aspects make a brew unstable. Stir it, steady it with Alchemical Salt, and brew at the right heat, or watch it boil over into Sludge.
• Discovery. Learn what each ingredient holds by brewing it, or reveal it with an Aspect Lens. Your Alchemist's Codex keeps track of everything you've found.
• 21 products. Elixirs like the Deep Miner's Draught and Featherfall Tonic, healing salves, tool oils that set your blade on fire or steal life, and throwable flasks.
• Mastery. Grind, press and distil your way to better brews, transmute materials in the Athanor, and maybe one day craft the Philosopher's Stone.
• A guided first brew to get you started, so nobody is left staring at an empty still.

Better Together

These three are built to work together and with the addons you already use. Alembic stills can be heated by a Hydraulics boiler. Sentinel's lockdowns can shut down your machines. Alembic draws ingredients from ExoticGarden, Cultivation, CrystamaeHistoria and Galactifun.

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Thank You

To the original Slimefun team: thank you for twelve and a half years of imagination, and for leaving the door open when you said goodbye. Everything we do stands on what you built, and we'll always honour that.

To Pter0x: a dear friend who helped lay the foundations we now stand on. Thousands of changes, thousands of late nights, and thousands of Coca-Colas later, here we are. None of this would exist without you. Thank you.

To our community: every player who has crafted, tinkered, reported a bug, or suggested something wonderfully ridiculous. You kept the lights on, the machines running and the ideas coming. You are the reason Slimefun is still here. Thank you, truly.

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Slimefun's story was never really over. It just needed someone to turn the page.

A new generation is writing the next chapter, and we're writing it with you.

Keep an eye on our Discord for testing news, sneak peeks and the chance to try these addons before anyone else. 🚀

— The Beyond Horizons Team