diff --git a/LaunchServer/source/response/ResponseThread.java b/LaunchServer/source/response/ResponseThread.java
index e48fa51..9724f72 100644
--- a/LaunchServer/source/response/ResponseThread.java
+++ b/LaunchServer/source/response/ResponseThread.java
@@ -80,7 +80,7 @@
         // Verify magic number
         int magicNumber = input.readInt();
         if (magicNumber != Launcher.PROTOCOL_MAGIC) {
-            if (magicNumber != 0x724724_00 + 16) { // 15.3- launcher protocol
+            if (magicNumber != Launcher.PROTOCOL_MAGIC - 1) { // Previous launcher protocol
                 output.writeBoolean(false);
                 throw new IOException(String.format("#%d Protocol magic mismatch", id));
             }
diff --git a/Launcher/source/Launcher.java b/Launcher/source/Launcher.java
index d804765..80461ba 100644
--- a/Launcher/source/Launcher.java
+++ b/Launcher/source/Launcher.java
@@ -80,7 +80,7 @@
     // Version info
     @LauncherAPI public static final String VERSION = "15.4";
     @LauncherAPI public static final String BUILD = readBuildNumber();
-    @LauncherAPI public static final int PROTOCOL_MAGIC = 0x724724_00 + 17;
+    @LauncherAPI public static final int PROTOCOL_MAGIC = 0x724724_00 + 23;
 
     // Constants
     @LauncherAPI public static final String RUNTIME_DIR = "runtime";