OpenJDK 11

src/main/java/me/finn/unlegitlibrary/addon/impl/AddonInfo.java

@@ -39,8 +39,8 @@ public class AddonInfo {
 
     @Override
     public boolean equals(Object obj) {
-        if (!(obj instanceof AddonInfo other)) return false;
-
+        if (!(obj instanceof AddonInfo)) return false;
+        AddonInfo other = (AddonInfo) obj;
         return other.name.equalsIgnoreCase(name) && other.version.equalsIgnoreCase(version) && other.author.equalsIgnoreCase(author);
     }
 

src/main/java/me/finn/unlegitlibrary/network/system/client/NetworkClient.java

@@ -202,7 +202,8 @@ public class NetworkClient extends DefaultMethodsOverrider {
                     continue;
                 }
 
-                if (received instanceof Integer id) {
+                if (received instanceof Integer) {
+                    int id = (Integer) received;
                     if (command.equalsIgnoreCase("s2c_connect")) {
                         clientID = id;
                         command = "";

src/main/java/me/finn/unlegitlibrary/network/system/server/ClientHandler.java

@@ -127,7 +127,8 @@ public class ClientHandler {
                     continue;
                 }
 
-                if (received instanceof Integer id) {
+                if (received instanceof Integer) {
+                    int id = (Integer) received;
                     if (command.equalsIgnoreCase("c2s_connect")) {
                         if (clientID == id) continue;
                         command = "";

src/main/java/me/finn/unlegitlibrary/number/Quaternion.java

@@ -76,7 +76,8 @@ public class Quaternion {
 
     @Override
     public final boolean equals(Object obj) {
-        if (!(obj instanceof Quaternion quaternion)) return false;
+        if (!(obj instanceof Quaternion)) return false;
+        Quaternion quaternion = (Quaternion) obj;
         return quaternion.x == x && quaternion.y == y && quaternion.z == z && quaternion.w == w;
     }
 

src/main/java/me/finn/unlegitlibrary/number/vector/Vector2.java

@@ -100,7 +100,8 @@ public class Vector2 {
 
     @Override
     public final boolean equals(Object obj) {
-        if (!(obj instanceof Vector2 vector2)) return false;
+        if (!(obj instanceof Vector2)) return false;
+        Vector2 vector2 = (Vector2) obj;
         return vector2.x == x && vector2.y == y;
     }
 

src/main/java/me/finn/unlegitlibrary/number/vector/Vector3.java

@@ -124,7 +124,8 @@ public class Vector3 {
 
     @Override
     public final boolean equals(Object obj) {
-        if (!(obj instanceof Vector3 vector3)) return false;
+        if (!(obj instanceof Vector3)) return false;
+        Vector3 vector3 = (Vector3) obj;
         return vector3.x == x && vector3.y == y && vector3.z == z;
     }