The JVM spec says:
"All bits of the access_flags item not assigned in Table 4.1-A are reserved for future use. They should be set to zero in generated class files and should be ignored by Java Virtual Machine implementations."
https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html

With MVT, we use JVM_ACC_VALUE == JVM_ACC_NATIVE to mark value type classes. The JVM_ACC_VALUE access flag should be ignored for class file versions < 53.1.