Install New Slab Variants on Minecraft

New Slab Variants fills the gaps in Minecraft's slab set. The project page says it adds more than 200 new slabs for building blocks that don't have one, with textures close to the vanilla look, so builds can use leaves, logs, ore blocks and more as half-height pieces. It must be installed on the server and in each player's game, and it runs on NeoForge and Fabric.

Checked against New Slab Variants 3.1.0 on NeoForge with Minecraft 26.1.2, October 2026.

Pick the right version

This mod has not moved to the newest Minecraft release yet. Modrinth's newest builds, 3.1.0 for NeoForge and Fabric, are for Minecraft 26.1 to 26.1.2. The NeoForge jar declares support for Minecraft 26.1 up to, but not including, 26.2, and the Fabric jar does the same. Older 3.0.1 builds cover Minecraft 1.20.1 and 1.21.1.

So set your server to NeoForge or Fabric on Minecraft 26.1.2. Open JAR Manager under More, choose the loader under Server software and 26.1.2 under Minecraft version, then press Apply change. The loader and version guide has the full steps. Leave Take a backup first ticked in the confirmation window. Minecraft 26.x runs on Java 25, which the panel selects for you.

What it needs

• NeoForge: MonoLib.
• Fabric: MonoLib and Fabric API. Modrinth only lists MonoLib, so the Mods tab will not offer Fabric API. Install it yourself from the same tab.

Install it

1. Open Mods under Content and keep the Modrinth chip selected in the source chip row at the top of the tab. The Game version filter starts on your server's version.
2. On Fabric, search for Fabric API and press Install first.
3. Search for New Slab Variants and press Install. When the "Needs" window lists MonoLib, press Install all.
4. Restart from the Console tab.

Open the Installed view and check that both mods appear without a Failed to load badge.

Players need it too

Modrinth lists the mod as required on both the client and the server. Players install the same build, MonoLib and (on Fabric) Fabric API for Minecraft 26.1.2. Join a modded server from your launcher covers the player side, and Fix the mismatched mod channel list error explains the refusal when mods differ.

Using the slabs

Slabs are crafted the vanilla way: three of a block in a row make six slabs. Many also have a stonecutter recipe, for example one block of amethyst gives two amethyst slabs. The project page says the new slabs work exactly like the default ones, and that the mod should cause no problems with other decorative mods.

Settings

The project page lists no settings, and on NeoForge the mod writes no config file of its own. After the first start there is no new_slab_variants file in the config folder of the File Manager; only MonoLib adds monolib-common.toml.

Updating

Press Check for updates in the Installed view. It only looks: if newer builds exist, the button becomes Update all (N), which asks you to confirm, and a row with a newer build gets its own Update button. Use either one, then restart the server. Before you move the server to a newer Minecraft version, use the Game version filter in the Mods tab to see which builds exist.

Common problems

• No results for your version: the mod has no build past 26.1.2 yet. Move the server back to 26.1.2 or wait for a release.
• The server stops at startup: read the last lines in the Console. A missing MonoLib or Fabric API is the usual cause. Fix mod and plugin errors on Minecraft covers the log.
• Players can't join: they are missing the mod or MonoLib.