$ javac --release 16 src/ImplicitPermits.java     (25.0.4.1+1-LTS)
src/ImplicitPermits.java:4: error: sealed classes are not supported in -source 16
public sealed class ImplicitPermits {
       ^
  (use -source 17 or higher to enable sealed classes)
1 error
exit=1

$ javac --release 17 src/ImplicitPermits.java     (25.0.4.1+1-LTS)
exit=0

$ javac --release 17 src/PaymentDemo.java     (25.0.4.1+1-LTS)
src/PaymentDemo.java:11: error: patterns in switch statements are not supported in -source 17
            case Card(String last4, long amount) -> amount * 2 / 100;     // 2 percent
                 ^
  (use -source 21 or higher to enable patterns in switch statements)
src/PaymentDemo.java:11: error: deconstruction patterns are not supported in -source 17