Update for Paper 26.1.1

src/main/kotlin/creator/custom/TemplateDescriptor.kt

@@ -40,7 +40,7 @@ data class TemplateDescriptor(
 
     companion object {
 
-        const val FORMAT_VERSION = 2
+        const val FORMAT_VERSION = 3
     }
 }
 

src/main/kotlin/creator/custom/derivation/FetchPaperDependencyVersionForMcVersion.kt

@@ -0,0 +1,109 @@
+/*
+ * Minecraft Development for IntelliJ
+ *
+ * https://mcdev.io/
+ *
+ * Copyright (C) 2026 minecraft-dev
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation, version 3.0 only.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.demonwav.mcdev.creator.custom.derivation
+
+import com.demonwav.mcdev.creator.custom.PropertyDerivation
+import com.demonwav.mcdev.creator.custom.TemplateValidationReporter
+import com.demonwav.mcdev.creator.custom.types.CreatorProperty
+import com.demonwav.mcdev.update.PluginUtil
+import com.demonwav.mcdev.util.MinecraftVersions
+import com.demonwav.mcdev.util.SemanticVersion
+import io.ktor.client.*
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import kotlinx.coroutines.runBlocking
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.int
+import kotlinx.serialization.json.jsonArray
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+
+class FetchPaperDependencyVersionForMcVersion : PreparedDerivation {
+
+    override fun derive(parentValues: List<Any?>): Any {
+        val version = parentValues[0] as SemanticVersion
+        if (version < MinecraftVersions.MC_26_1) {
+            return "${version}-R0.1-SNAPSHOT";
+        }
+
+        val isMaven = (parentValues[1] as String) == "Maven"
+        if (isMaven) {
+            val latestBuild = fetchPaperBuildData(version.toString());
+            return "${version}.build.${latestBuild.id}-${latestBuild.channel}"
+        }
+        return "${version}.build.+"
+    }
+
+    private fun fetchPaperBuildData(version: String): PaperBuild {
+        return runBlocking {
+            val client = HttpClient()
+            val response = client.get("https://fill.papermc.io/v3/projects/paper/versions/${version}/builds", block = {
+                this.header(
+                    "User-Agent",
+                    "minecraft-dev/${PluginUtil.pluginVersion} (https://github.com/minecraft-dev/MinecraftDev)"
+                )
+            })
+            if (response.status.isSuccess()) {
+                return@runBlocking Json.parseToJsonElement(response.bodyAsText()).jsonArray[0]
+                    .let { build ->
+                        return@let PaperBuild(
+                            build.jsonObject["id"]!!.jsonPrimitive.int,
+                            build.jsonObject["channel"]!!.jsonPrimitive.content.lowercase()
+                        )
+                    }
+            } else {
+                throw IllegalStateException("Failed to fetch latest Paper build for version ${version}: ${response.bodyAsText()}")
+            }
+        }
+    }
+
+    private data class PaperBuild(
+        val id: Int,
+        val channel: String,
+    );
+
+    companion object : PropertyDerivationFactory {
+
+        override fun create(
+            reporter: TemplateValidationReporter,
+            parents: List<CreatorProperty<*>?>?,
+            derivation: PropertyDerivation
+        ): PreparedDerivation? {
+            if (parents.isNullOrEmpty()) {
+                reporter.error("Expected a parent")
+                return null
+            }
+
+            if (!parents[0]!!.acceptsType(SemanticVersion::class.java)) {
+                reporter.error("First parent must produce a semantic version")
+                return null
+            }
+
+            if (!parents[1]!!.acceptsType(String::class.java)) {
+                reporter.error("Second parent must produce a string")
+                return null
+            }
+
+            return FetchPaperDependencyVersionForMcVersion()
+        }
+    }
+}

src/main/kotlin/creator/custom/types/StringCreatorProperty.kt

@@ -25,6 +25,7 @@ import com.demonwav.mcdev.creator.custom.CreatorContext
 import com.demonwav.mcdev.creator.custom.PropertyDerivation
 import com.demonwav.mcdev.creator.custom.TemplatePropertyDescriptor
 import com.demonwav.mcdev.creator.custom.TemplateValidationReporter
+import com.demonwav.mcdev.creator.custom.derivation.FetchPaperDependencyVersionForMcVersion
 import com.demonwav.mcdev.creator.custom.derivation.PreparedDerivation
 import com.demonwav.mcdev.creator.custom.derivation.ReplacePropertyDerivation
 import com.demonwav.mcdev.creator.custom.derivation.SelectPropertyDerivation
@@ -73,6 +74,11 @@ class StringCreatorProperty(
             ReplacePropertyDerivation.create(reporter, parents, derives)
         }
 
+        "fetchPaperDependencyVersionForMcVersion" -> {
+            val parents = collectDerivationParents(reporter)
+            FetchPaperDependencyVersionForMcVersion.create(reporter, parents, derives)
+        }
+
         null -> {
             // No need to collect parent values for this one because it is not used
             SelectPropertyDerivation.create(reporter, emptyList(), derives)

src/main/kotlin/platform/mixin/util/MinecraftMissingLVTChecker.kt

@@ -32,7 +32,7 @@ class MinecraftMissingLVTChecker : MissingLVTChecker {
             !className.startsWith("net.minecraft.") && !className.startsWith("com.mojang.blaze3d.") -> false
             else -> {
                 val mcVersion = context.mcVersion
-                mcVersion != null && mcVersion <= MinecraftVersions.MC25_4
+                mcVersion != null && mcVersion <= MinecraftVersions.MC_1_21_11
             }
         }
     }

src/main/kotlin/util/MinecraftVersions.kt

@@ -46,13 +46,14 @@ object MinecraftVersions {
     val MC1_20_6 = SemanticVersion.release(1, 20, 6)
     val MC1_21 = SemanticVersion.release(1, 21)
     val MC1_21_1 = SemanticVersion.release(1, 21, 1)
-    val MC25_4 = SemanticVersion.release(25, 4) // placeholder till we know what the last 2025 winter drop version is
+    val MC_1_21_11 = SemanticVersion.release(1, 21, 11)
+    val MC_26_1 = SemanticVersion.release(26, 1)
 
     fun requiredJavaVersion(minecraftVersion: SemanticVersion) = when {
         minecraftVersion <= MC1_16_5 -> JavaSdkVersion.JDK_1_8
         minecraftVersion <= MC1_17_1 -> JavaSdkVersion.JDK_16
         minecraftVersion <= MC1_20_4 -> JavaSdkVersion.JDK_17
-        minecraftVersion<= MC25_4 -> JavaSdkVersion.JDK_21
+        minecraftVersion <= MC_1_21_11 -> JavaSdkVersion.JDK_21
         else -> JavaSdkVersion.JDK_25
     }
 }