Not able to obfuscate, getting error - Unsupported class file major version 61

[yogeshnikam671]

Exception in thread "main" java.lang.IllegalArgumentException: Unsupported class file major version 61 at org.objectweb.asm.ClassReader.(ClassReader.java:196) at org.objectweb.asm.ClassReader.(ClassReader.java:177) at org.objectweb.asm.ClassReader.(ClassReader.java:163) at dev.tigr.nebulous.Nebulous.openJar(Nebulous.kt:115) at dev.tigr.nebulous.Nebulous.openFile(Nebulous.kt:95) at dev.tigr.nebulous.Nebulous.run(Nebulous.kt:55) at dev.tigr.nebulous.MainKt.main(Main.kt:25)