diff --git a/build.gradle.kts b/build.gradle.kts
index 7d53604..59df33c 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -8,6 +8,8 @@ repositories {
 }
 
 preprocess {
+    val fabric12100 = createNode("1.21-fabric", 1_21_00, "yarn")
+    val neoforge12100 = createNode("1.21-neoforge", 1_21_00, "yarn")
     val fabric12006 = createNode("1.20.6-fabric", 1_20_06, "yarn")
     val neoforge12006 = createNode("1.20.6-neoforge", 1_20_06, "yarn")
     val fabric12004 = createNode("1.20.4-fabric", 1_20_04, "yarn")
@@ -21,15 +23,17 @@ preprocess {
     val fabric11802 = createNode("1.18.2-fabric", 1_18_02, "yarn")
     val forge11802 = createNode("1.18.2-forge", 1_18_02, "srg")
 
-    fabric12006.link(neoforge12006)
-    neoforge12006.link(neoforge12004)
-    neoforge12004.link(fabric12004)
-    fabric12004.link(fabric12001)
-    fabric12001.link(forge12001)
-    forge12001.link(forge11904)
-    forge11904.link(fabric11904)
-    fabric11904.link(fabric11902)
-    fabric11902.link(forge11902)
-    forge11902.link(forge11802)
-    forge11802.link(fabric11802)
+    fabric12100.link(neoforge12100)
+    neoforge12100.link(neoforge12006)
+    neoforge12006.link(fabric12006)
+    fabric12006.link(fabric12004)
+    fabric12004.link(neoforge12004)
+    neoforge12004.link(forge12001)
+    forge12001.link(fabric12001)
+    fabric12001.link(fabric11904)
+    fabric11904.link(forge11904)
+    forge11904.link(forge11902)
+    forge11902.link(fabric11902)
+    fabric11902.link(fabric11802)
+    fabric11802.link(forge11802)
 }
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 5abe3d4..675da57 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -31,6 +31,8 @@ listOf(
     "1.20.4-fabric",
     "1.20.6-neoforge",
     "1.20.6-fabric",
+    "1.21-neoforge",
+    "1.21-fabric",
 ).forEach { version ->
     include(":$version")
     project(":$version").apply {
diff --git a/version.gradle.kts b/version.gradle.kts
index e75fbaf..7c57bae 100644
--- a/version.gradle.kts
+++ b/version.gradle.kts
@@ -115,6 +115,7 @@ unimined.minecraft {
         }
         isNeoForge -> neoForged {
             loader(when (mcVersion) {
+                1_21_00 -> "0.4-beta"
                 1_20_06 -> "21-beta"
                 1_20_04 -> "69-beta"
                 else -> throw IllegalStateException("Unknown NeoForge version for $mcVersionString")
@@ -259,6 +260,7 @@ dependencies {
 
     if (isFabric) {
         when (mcVersion) {
+            1_21_00 -> "11.0.0-beta.1"
             1_20_06 -> "10.0.0-beta.1"
             1_20_04 -> "9.0.0"
             1_20_01 -> "7.2.2"
@@ -280,6 +282,7 @@ dependencies {
 
     if (isFabric) {
         when (mcVersion) {
+            1_21_00 -> "0.100.1+1.21"
             1_20_06 -> "0.100.0+1.20.6"
             1_20_04 -> "0.97.1+1.20.4"
             1_20_01 -> "0.92.2+1.20.1"
@@ -381,6 +384,7 @@ tasks.processResources {
     // TODO: Remove pack.mcmeta in 1.20.4
     filesMatching("pack.mcmeta") {
         expand("pack_format" to when {
+            mcVersion >= 1_21_00 -> 34
             mcVersion >= 1_20_05 -> 32
             mcVersion >= 1_20_03 -> 22
             mcVersion >= 1_20_02 -> 18