Release 0.30.15 is incompatible with Purpur 1.21.11-2540, but shows up as the most recent compatible version on Modrinth

[4Ply]

Similar to #181: on Purpur 1.21.11-2540, I see the following error when using the 0.30.15 release (tested both the Modrinth and Github jars).

However 0.31.0 works fine, which is great! I presume that relates to #167.

I think the issue here is that 0.30.15 is not meant to be compatible with Purpur on 1.21.11 now? If so, can that release be marked as incompatible, since a lot of server tooling uses the latest release as opposed to the highest-numbered release, meaning that 0.30.15 gets pulled because it was published more recently.

[00:30:45 INFO]: [bootstrap] Running Java 21 (OpenJDK 64-Bit Server VM 21.0.6+7-LTS; Eclipse Adoptium Temurin-21.0.6+7) on Linux 6.17.9-arch1-1 (amd64)
[00:30:45 INFO]: [bootstrap] Loading Purpur 1.21.11-2540-HEAD@7c95345 (2025-12-20T04:49:29Z) for Minecraft 1.21.11

[00:30:52 INFO]: [InvSee++] Enabling InvSeePlusPlus v0.30.15
[00:30:52 INFO]: [InvSee++] Detected server software: Paper version 1.21.11
[00:30:52 ERROR]: Error occurred while enabling InvSeePlusPlus v0.30.15 (Is it up to date?)
java.lang.NoClassDefFoundError: net/minecraft/world/entity/player/EntityHuman
	at InvSee++.jar//com.janboerman.invsee.spigot.Impl_1_21_11.<init>(Setup.java:143) ~[?:?]
	at InvSee++.jar//com.janboerman.invsee.spigot.SetupImpl.lambda$static$15(Setup.java:174) ~[?:?]
	at InvSee++.jar//com.janboerman.invsee.spigot.Setup.setup(Setup.java:41) ~[?:?]
	at InvSee++.jar//com.janboerman.invsee.spigot.InvseePlusPlus.onEnable(InvseePlusPlus.java:86) ~[?:?]
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:279) ~[purpur-api-1.21.11-R0.1-SNAPSHOT.jar:?]
	at io.papermc.paper.plugin.manager.PaperPluginInstanceManager.enablePlugin(PaperPluginInstanceManager.java:202) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.enablePlugin(PaperPluginManagerImpl.java:109) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:520) ~[purpur-api-1.21.11-R0.1-SNAPSHOT.jar:?]
	at org.bukkit.craftbukkit.CraftServer.enablePlugin(CraftServer.java:653) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at org.bukkit.craftbukkit.CraftServer.enablePlugins(CraftServer.java:610) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at net.minecraft.server.MinecraftServer.initPostWorld(MinecraftServer.java:640) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at net.minecraft.server.dedicated.DedicatedServer.initServer(DedicatedServer.java:408) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1275) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:392) ~[purpur-1.21.11.jar:1.21.11-2540-7c95345]
	at java.base/java.lang.Thread.run(Unknown Source) ~[?:?]
Caused by: java.lang.ClassNotFoundException: net.minecraft.world.entity.player.EntityHuman
	at org.bukkit.plugin.java.PluginClassLoader.loadClass0(PluginClassLoader.java:208) ~[purpur-api-1.21.11-R0.1-SNAPSHOT.jar:?]
	at org.bukkit.plugin.java.PluginClassLoader.loadClass(PluginClassLoader.java:175) ~[purpur-api-1.21.11-R0.1-SNAPSHOT.jar:?]
	at java.base/java.lang.ClassLoader.loadClass(Unknown Source) ~[?:?]
	... 15 more
[00:30:52 INFO]: [InvSee++] Disabling InvSeePlusPlus v0.30.15

[Jannyboy11]

No, actually, it is meant to be compatible, but it will only be compatible once Purpur integrates the Spigot plugin bytecode remapper. Purpur didn't yet do this, because Paper didn't merge it yet: PaperMC/Paper#13388
You are running server software that is still considered alpha/experimental, so please consider encountered issues could be bugs in the server, not necessarily in the plugins.

Besides, InvSee++ v0.30.15 already works fine om Spigot 1.21.11, but Modrinth doesn't let me specify Minecraft versions per loader type.

[Jannyboy11]

Closing this issue since you already found a working solution.

[Jannyboy11]

And yes indeed it relates to #167.