diff --git a/src/main/java/eu/m724/tweaks/TweaksPlugin.java b/src/main/java/eu/m724/tweaks/TweaksPlugin.java
index 42975fc..e427283 100644
--- a/src/main/java/eu/m724/tweaks/TweaksPlugin.java
+++ b/src/main/java/eu/m724/tweaks/TweaksPlugin.java
@@ -58,6 +58,23 @@ public class TweaksPlugin extends MStatsPlugin {
         new Language(Locale.of(config.locale())); // TODO
         DebugLogger.fine(Language.getString("languageNotice", Language.getString("language"), Language.getString("languageEnglish")));
 
+        var runningVersion = getServer().getBukkitVersion();
+        var targetVersion = getTargetVersion();
+
+        if (!runningVersion.equals(targetVersion)) {
+            // the incompatibility can be between 1.21.4-R0.1-SNAPSHOT and 1.21.4-R1-SNAPSHOT
+            var runningMc = runningVersion.split("-")[0];
+            var targetMc = targetVersion.split("-")[0];
+            if (!runningMc.equals(targetMc)) {
+                targetVersion = targetMc;
+                runningVersion = runningMc;
+            }
+
+            getLogger().warning("This plugin was built for %s. This server is running %s.".formatted(targetVersion, runningVersion));
+            getLogger().warning("Some modules will not work. Disable those modules, or make a compatible build yourself:");
+            getLogger().warning("https://git.m724.eu/Minecon724/tweaks724/src/branch/master/docs/BUILDING.md");
+        }
+
         /* start modules */
 
         if (config.worldborderHide()) {
@@ -141,6 +158,15 @@ public class TweaksPlugin extends MStatsPlugin {
         DebugLogger.fine("Took %.3f milliseconds".formatted((System.nanoTime() - start) / 1000000.0));
     }
 
+    private String getTargetVersion() {
+        var permission = getServer().getPluginManager().getPermission("7weaks724.ignore.this");
+
+        var desc = permission.getDescription().substring("Internal, not for use. ".length()).split(",");
+        var version = desc[0];
+
+        return version;
+    }
+
     public boolean hasResource(String resource) {
         return this.getClassLoader().getResource(resource) != null;
     }
diff --git a/src/main/resources/plugin.yml b/src/main/resources/plugin.yml
index fac4b46..7882556 100644
--- a/src/main/resources/plugin.yml
+++ b/src/main/resources/plugin.yml
@@ -42,6 +42,9 @@ commands:
     permission: tweaks724.servkill
 
 permissions:
+  7weaks724.ignore.this:
+    description: "Internal, not for use. ${project.spigot.version}"
+    default: false
   tweaks724:
     chatmanage:
       default: true