diff --git a/Launcher/source-authlib/minecraft/MinecraftProfileTexture.java b/Launcher/source-authlib/minecraft/MinecraftProfileTexture.java
index cc13bc0..c3e30a6 100644
--- a/Launcher/source-authlib/minecraft/MinecraftProfileTexture.java
+++ b/Launcher/source-authlib/minecraft/MinecraftProfileTexture.java
@@ -4,7 +4,7 @@
 import java.util.EnumSet;
 import java.util.Set;
 
-public class MinecraftProfileTexture {
+public final class MinecraftProfileTexture {
     public static final Set<Type> PROFILE_TEXTURE_TYPES = Collections.unmodifiableSet(EnumSet.allOf(Type.class));
     public static final int PROFILE_TEXTURE_COUNT = PROFILE_TEXTURE_TYPES.size();
 
diff --git a/Launcher/source-authlib/yggdrasil/CompatBridge.java b/Launcher/source-authlib/yggdrasil/CompatBridge.java
index e701174..225f00a 100644
--- a/Launcher/source-authlib/yggdrasil/CompatBridge.java
+++ b/Launcher/source-authlib/yggdrasil/CompatBridge.java
@@ -14,7 +14,7 @@
 
 // Used to bypass Launcher's class name obfuscation and access API
 @LauncherAPI
-public class CompatBridge {
+public final class CompatBridge {
     public static final int PROFILES_MAX_BATCH_SIZE = BatchProfileByUsernameRequest.MAX_BATCH_SIZE;
 
     private CompatBridge() {
diff --git a/Launcher/source-authlib/yggdrasil/CompatProfile.java b/Launcher/source-authlib/yggdrasil/CompatProfile.java
index 473e571..6289a7d 100644
--- a/Launcher/source-authlib/yggdrasil/CompatProfile.java
+++ b/Launcher/source-authlib/yggdrasil/CompatProfile.java
@@ -8,7 +8,7 @@
 import launcher.helper.SecurityHelper;
 
 @LauncherAPI
-public class CompatProfile {
+public final class CompatProfile {
     public static final String SKIN_URL_PROPERTY = ClientLauncher.SKIN_URL_PROPERTY;
     public static final String SKIN_DIGEST_PROPERTY = ClientLauncher.SKIN_DIGEST_PROPERTY;
     public static final String CLOAK_URL_PROPERTY = ClientLauncher.CLOAK_URL_PROPERTY;
diff --git a/Launcher/source-authlib/yggdrasil/LegacyBridge.java b/Launcher/source-authlib/yggdrasil/LegacyBridge.java
index 2e17530..7cb5747 100644
--- a/Launcher/source-authlib/yggdrasil/LegacyBridge.java
+++ b/Launcher/source-authlib/yggdrasil/LegacyBridge.java
@@ -10,7 +10,7 @@
 
 // Used by 1.6.4 and below versions
 @LauncherAPI
-public class LegacyBridge {
+public final class LegacyBridge {
     private LegacyBridge() {
     }