diff --git a/build.gradle.kts b/build.gradle.kts
index 7d53604c..5bb3b0b1 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,6 +1,6 @@
 plugins {
     id("io.github.gaming32.gradle.preprocess-root") version "0.4.4"
-    id("xyz.wagyourtail.unimined") version "1.2.4" apply false
+    id("xyz.wagyourtail.unimined") version "1.2.9" apply false
 }
 
 repositories {
@@ -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 5abe3d44..675da574 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/src/main/java/io/github/gaming32/worldhost/ResourceLocations.java b/src/main/java/io/github/gaming32/worldhost/ResourceLocations.java
index 79b41a58..a6f384b9 100644
--- a/src/main/java/io/github/gaming32/worldhost/ResourceLocations.java
+++ b/src/main/java/io/github/gaming32/worldhost/ResourceLocations.java
@@ -3,14 +3,35 @@
 import net.minecraft.resources.ResourceLocation;
 
 public final class ResourceLocations {
+    private static final String WORLD_HOST_NAMESPACE = "world-host";
+    //#if MC >= 1.19.4
+    private static final ResourceLocation WORLD_HOST_TEMPLATE = namespaced(WORLD_HOST_NAMESPACE, "");
+    //#endif
+
     private ResourceLocations() {
     }
 
     public static ResourceLocation minecraft(String path) {
-        return new ResourceLocation(ResourceLocation.DEFAULT_NAMESPACE, path);
+        //#if MC >= 1.21
+        return ResourceLocation.withDefaultNamespace(path);
+        //#else
+        //$$ return new ResourceLocation(ResourceLocation.DEFAULT_NAMESPACE, path);
+        //#endif
     }
 
     public static ResourceLocation worldHost(String path) {
-        return new ResourceLocation("world-host", path);
+        //#if MC >= 1.19.4
+        return WORLD_HOST_TEMPLATE.withPath(path);
+        //#else
+        //$$ return new ResourceLocation(WORLD_HOST_NAMESPACE, path);
+        //#endif
+    }
+
+    public static ResourceLocation namespaced(String namespace, String path) {
+        //#if MC >= 1.21
+        return ResourceLocation.fromNamespaceAndPath(namespace, path);
+        //#else
+        //$$ return new ResourceLocation(namespace, path);
+        //#endif
     }
 }
diff --git a/src/main/java/io/github/gaming32/worldhost/mixin/MixinGameRenderer.java b/src/main/java/io/github/gaming32/worldhost/mixin/MixinGameRenderer.java
index 8bd9ceb7..0fe2e5a1 100644
--- a/src/main/java/io/github/gaming32/worldhost/mixin/MixinGameRenderer.java
+++ b/src/main/java/io/github/gaming32/worldhost/mixin/MixinGameRenderer.java
@@ -53,7 +53,12 @@ private void toastRender(CallbackInfo ci) {
             //#else
             new GuiGraphics(minecraft, renderBuffers.bufferSource()),
             //#endif
-            mouseX, mouseY, minecraft.getFrameTime()
+            mouseX, mouseY,
+            //#if MC >= 1.21
+            minecraft.getTimer().getRealtimeDeltaTicks()
+            //#else
+            //$$ minecraft.getFrameTime()
+            //#endif
         );
     }
     //#endif
diff --git a/src/main/resources/META-INF/neoforge.mods.toml b/src/main/resources/META-INF/neoforge.mods.toml
index 0a3cb7c2..b959c0e5 100644
--- a/src/main/resources/META-INF/neoforge.mods.toml
+++ b/src/main/resources/META-INF/neoforge.mods.toml
@@ -27,9 +27,9 @@ side = "BOTH"
 [[dependencies.world_host]]
 modId = "minecraft"
 ##if MC == 1.20.6
-versionRange = "[1.20.5,1.20.7)"
+#?? versionRange = "[1.20.5,1.20.7)"
 ##else
-#?? versionRange = "[$mc_version]"
+versionRange = "[$mc_version]"
 ##endif
 type = "required"
 ordering = "NONE"
diff --git a/src/main/resources/fabric.mod.json b/src/main/resources/fabric.mod.json
index 0ad2861d..333c8b2b 100644
--- a/src/main/resources/fabric.mod.json
+++ b/src/main/resources/fabric.mod.json
@@ -35,9 +35,9 @@
     //#elseif MC == 1.20.4
     //?? "minecraft": ">=1.20.3- <1.20.5",
     //#elseif MC == 1.20.6
-    "minecraft": ">=1.20.5- <1.20.7",
+    //?? "minecraft": ">=1.20.5- <1.20.7",
     //#else
-    //?? "minecraft": "$mc_version",
+    "minecraft": "$mc_version",
     //#endif
     "fabric-resource-loader-v0": "*"
   },
diff --git a/version.gradle.kts b/version.gradle.kts
index e75fbaf1..6e3fbb96 100644
--- a/version.gradle.kts
+++ b/version.gradle.kts
@@ -113,8 +113,9 @@ unimined.minecraft {
             })
             mixinConfig("world-host.mixins.json")
         }
-        isNeoForge -> neoForged {
+        isNeoForge -> neoForge {
             loader(when (mcVersion) {
+                1_21_00 -> "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
diff --git a/versions/mainProject b/versions/mainProject
index 304eaace..dfdd5113 100644
--- a/versions/mainProject
+++ b/versions/mainProject
@@ -1 +1 @@
-1.20.6-fabric
\ No newline at end of file
+1.21-fabric
\ No newline at end of file